{
  "id": "united-states",
  "title": "United States",
  "lang": "en",
  "source_lang": "en",
  "summary": "The United States is a federal constitutional republic of 50 states and several territories in North America, with about 340 million people and the largest nominal GDP of any economy.",
  "category": "geography",
  "subcategory": "",
  "type": "place",
  "aliases": [
    "USA",
    "US",
    "United States of America",
    "America"
  ],
  "generated_at": "2026-10-09",
  "model": "pro/claude-haiku-5-5",
  "url": "https://aiwiki.page/en/united-states/",
  "translations": {
    "zh-Hans": {
      "url": "https://aiwiki.page/zh/united-states/",
      "json": "https://aiwiki.page/zh/united-states.json"
    }
  },
  "sections": [
    {
      "heading": "",
      "text": "The United States of America is a federal constitutional republic in North America, made up of 50 states, the District of Columbia, and several inhabited territories. The contiguous 48 states lie between the Atlantic and Pacific oceans and share land borders with Canada and Mexico, while Alaska and Hawaii are separated from them. Its total area of about 9.8 million square kilometres makes it one of the largest countries by area. With a population of roughly 340 million, it is the third most populous country, and it has the largest nominal gross domestic product of any economy. Its geography ranges from the mountain systems of the West and the glacier-carved landscapes of Alaska to the tropical islands of Hawaii and southern Florida, which gives it a wide variety of climates and ecosystems.\n\nThis entry treats the United States as a physical, human, and political geography. It begins with the country's definition, territorial extent, and regional divisions, then turns to the physical landscape: landforms, tectonic history, river and aquifer systems, climate, and biodiversity. It then covers the people and settlement patterns, from pre-colonial archaeological evidence through the territorial expansion that shaped the modern borders, and the federal constitutional system of government. Later sections address the economy, culture, education and research, infrastructure, health, foreign relations, environmental management, and questions that remain open or contested.\n\nTaken together, these sections show how the country's geography has shaped its settlement, economy, and institutions, and how physical features and human decisions interact in its present-day landscape."
    },
    {
      "heading": "Definition, Name, and Territorial Extent",
      "text": "Name and origins\n\nThe name \"United States of America\" was adopted during the American Revolution and became fixed in the founding documents. Before 1776 the union was commonly called the \"United Colonies.\" Richard Henry Lee's June 1776 resolution spoke of \"these United Colonies\" as free and independent states, and it was adopted on 2 July. Thomas Jefferson's June draft of the Declaration of Independence began with the phrase \"United States of America,\" but the engrossed text adopted on 4 July used a lowercase adjective, describing \"the thirteen united States of America.\" On 9 September 1776, the Second Continental Congress formally replaced \"United Colonies\" with \"United States\" in its official instruments. The name then appeared in the Articles of Confederation and in the Preamble of the Constitution, which was signed in 1787 and took effect on 4 March 1789 after ratification by nine of the thirteen states. Historians often note that a collective national identity took more than a decade to emerge, so the 1789 Constitution marked a second foundational stage rather than a completed one. The demonym \"American\" has a parallel history; it was first used by British writers in a pejorative sense before the colonists adopted it.\n\nConstituent units and territories\n\nThe country consists of 50 states, the District of Columbia, and a set of insular areas called territories. Each state holds subsidiary sovereignty and shares jurisdiction with the federal government. Under the Constitution, Congress holds exclusive legislative authority over the District of Columbia, the federal capital at Washington, and full lawmaking power over the territories under the Territorial Clause.\n\nThe territories fall into two groups. Five are permanently inhabited: American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the United States Virgin Islands. Puerto Rico and the Northern Mariana Islands are commonwealths, Guam and the Virgin Islands are organized unincorporated territories, and American Samoa is unorganized and unincorporated. Residents of American Samoa are U.S. nationals rather than citizens. Nine are uninhabited or have no permanent population: Baker Island, Howland Island, Jarvis Island, Johnston Atoll, Kingman Reef, Midway Atoll, Navassa Island, Palmyra Atoll, and Wake Island. These nine are collectively known as the United States Minor Outlying Islands. Palmyra Atoll is the only incorporated territory, meaning the full Constitution applies there. Bajo Nuevo Bank and Serranilla Bank are claimed but counted differently across sources, which is why totals of 14 and 16 territories both appear. The legal status of the territories rests on the Insular Cases of the early twentieth century, which distinguished incorporated from unincorporated areas.\n\nTotal, land, and water area\n\nEstimates depend on method. The CIA World Factbook gives a total area of 9,833,517 km², of which 9,147,593 km² is land and 685,924 km² is water, and it includes only the 50 states and the District of Columbia. The United Nations Statistics Division gives 9,629,091 km², and the Encyclopaedia Britannica gives 9,525,067 km², which includes the Great Lakes area but excludes coastal and territorial waters. The differences reflect whether coastal waters, the Great Lakes, and territorial waters are counted. On the CIA basis, the country is about half the size of Russia, slightly larger than China, and more than twice the size of the European Union. By total area it ranks third or fourth, behind Russia and Canada, depending on the edition and source. When the Exclusive Economic Zone is included, the country has the second-largest maritime zone in the world, at about 11.35 million km².\n\nLand borders and maritime boundaries\n\nThe contiguous states share land borders with Canada and Mexico. The CIA archive lists a total land boundary of 12,002 km, with 8,891 km shared with Canada, including 2,475 km adjoining Alaska, and 3,111 km shared with Mexico. Other compilations give slightly different figures, such as 12,036 km in total. The Atlantic, Pacific, Gulf, and Arctic coastlines together run about 19,900 km. The country's territorial sea extends 12 nautical miles, its contiguous zone 24 nautical miles, and its Exclusive Economic Zone 200 nautical miles. The Guantánamo Bay Naval Base in Cuba is leased to the United States, and the leased area is treated as part of Cuba for boundary purposes.\n\nAlaska and Hawaii are not contiguous with the rest of the country. Alaska borders Canada on its eastern and southeastern flanks, so it is joined to the mainland only through Canadian territory, while Hawaii is an island state in the central Pacific Ocean. Their separation from the contiguous states is central to their geography, which is discussed in the regional divisions section."
    },
    {
      "heading": "Regions and Subnational Divisions",
      "text": "Official Census Bureau regions\n\nThe Census Bureau's statistical geography nests nine divisions inside four regions: nine census divisions nested in four census regions. The Northeast combines New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont) with the Middle Atlantic division of New Jersey, New York and Pennsylvania. The Midwest is split into an East North Central division and a West North Central division, which together cover twelve states. South: South Atlantic + East South Central + West South Central. The South holds the largest number of states, and the West, which is Mountain + Pacific, takes in Alaska and Hawaii along with the interior Mountain states and the Pacific coast. The scheme is not a level of government. It is a grouping used for statistics. The Census Bureau defines four major regions, which are further divided into nine divisions. The arrangement has been in use since 1950.\n\nThe Census boundaries often surprise readers who expect cultural lines. Delaware, Maryland and the District of Columbia are assigned to the South, even though they are commonly thought of as Mid-Atlantic and are sometimes grouped with the Northeast. Missouri and Kansas sit in the Midwest, but they overlap culturally with both the South and the West. Texas and Oklahoma are part of the Census South, yet most Americans consider them part of the Southwest.\n\nInformal cultural regions\n\nIn everyday speech, Americans often use a five-part scheme: the United States is divided into five regions: Northeast, Southeast, Midwest, Southwest, and West. This model is not standardized. The five and seven US region models are informal and not standardized. State groupings can vary depending on the source and boundaries are often adjusted for teaching, cultural reference, or simplified maps. The Southeast usually absorbs most of the Census South east of Texas, while the Southwest is defined as Arizona, New Mexico, and often Texas, Oklahoma, and Nevada. Under the Census, Arizona, New Mexico and Nevada fall within the West. Some scholarly mappings of cultural space go further. One study of social-media language found that its analysis divides the South into two regions, splitting Texas off from the rest of the Southeast, and splits the Midwest off from the rest of the North, producing discontinuous regions rather than contiguous blocks.\n\nOther labels are cultural or economic rather than geographic. The Rust Belt refers loosely to the post-industrial states around the Great Lakes; the Sun Belt stretches roughly from the Carolinas across the South to California; the Bible Belt describes a culturally Protestant swath of the South and Lower Midwest. The Pacific Northwest is also informal. It consistently includes the states of Oregon and Washington, and some sources extend it to Idaho, Montana, Wyoming and southeastern Alaska.\n\nRegional identities\n\nRegional identities have grown along these lines but do not match any single boundary. Southern identity, for example, is often described in terms of a belt running from the Mason–Dixon line toward the Ohio River, a definition that differs from the Census South, which reaches into Delaware, Maryland and the District of Columbia. Regional dialects, speech patterns and food traditions likewise follow historical settlement patterns rather than administrative lines, so a state's official region tells a reader little about its cultural affinities. The official and informal schemes are therefore best read together: the Census grid for statistics and the informal labels for travel, culture and self-description.\n\nAlaska and Hawaii\n\nAlaska and Hawaii are the only non-contiguous states. The 48 contiguous states plus the District of Columbia form one connected block of land. Alaska is one of two US states that are not bordered by another state, the other state being Hawaii. Alaska is separated from the lower 48 by Canadian territory, and it has a maritime boundary with Russia across the Bering Strait. Although it lies on the North American continent, it is not part of the contiguous block, and it is often described as an exclave of the continental United States. It is the largest state by area, covering a total area of approximately 663,268 square miles.\n\nHawaii is further removed. It lies about 2,400 miles off the West Coast in the middle of the Pacific, and geographers generally group it with Oceania rather than North America. Its landscape is an archipelago of volcanic islands, and its isolation is a major factor in its economy and logistics. The state joined as the 50th state on August 21, 1959, a few months after Alaska. Both states fall in the Census West region, which makes it the most geographically varied of the four regions."
    },
    {
      "heading": "Physical Landforms",
      "text": "The Eastern Highlands and Coastal Plain\n\nThe mountain ranges of the East are old and heavily worn. The Appalachians are eroded remnants of what were once much higher mountain ranges, and they separate the seaboard from the interior lowlands along much of the eastern United States. The range is divided into several provinces, including the Blue Ridge, the Valley and Ridge, the Appalachian Plateau, and the New England province. Soils in most of the region are shallow, and steep slopes are difficult to farm and poorly suited to mechanized agriculture. Small pockets of lowland also constrain large-scale urban and industrial growth.\n\nEast of the mountains lies the Atlantic Coastal Plain, which is located along the Atlantic Ocean and the Gulf of Mexico. Its subdivisions run from the Embayed and Sea Island sections of the Atlantic seaboard to the Floridian section, the East and West Gulf coastal plains, and the Mississippi Alluvial Plain. Its low relief and proximity to the sea have made it a corridor for ports and settlement.\n\nThe Interior Lowlands and Great Plains\n\nBetween the Appalachians and the Rocky Mountains lies the Interior Lowlands, a broad and mostly flat region. It extends from central Saskatchewan in Canada to the rim of the Coastal Plain and is bounded by the Great Plains on the west, the Canadian Shield on the north and east, and the Appalachian Mountains on the east. Its rocks are notably undisturbed: the Interior Lowlands consist largely of undeformed Paleozoic marine rocks, mainly limestones and shales, that glaciers and rivers have since carved and shaped. The region has experienced little tectonic activity for a very long time, and on its northern edge, glaciers carved the basins that now hold the Great Lakes.\n\nWest of the Interior Lowlands the land rises into the Great Plains. Its sediments were eroded from the Rocky Mountains and are substantially younger, dating to the Mesozoic and Cenozoic, with a higher proportion of coarser clastic material. The surface is made up of flat grasslands and gradually increases in elevation westward. The Plains contain subdivisions such as the glaciated and unglaciated Missouri Plateau, the Black Hills, the High Plains, and the Edwards Plateau in Texas. The Mississippi and Missouri systems drain this central interior, linking the river networks and drainage basins of the continent's center to the Gulf of Mexico.\n\nThe Western Mountains and Plateaus\n\nThe West is structurally more varied. The Rocky Mountains form a long chain divided into southern, middle, and northern sections, including the Wyoming Basin. The Intermontane region lies between the Pacific mountain system and the Rockies, and it contains mountain ranges, plateaus, basins, and gorges. The Basin and Range region lies west of the Rocky Mountains and contains isolated mountain ranges rising from lower basins. Its subdivisions include the Great Basin section and the Sonoran Desert.\n\nThe Colorado Plateau is an elevated block with its own internal divisions, including the High Plateaus of Utah, the Canyon Lands, the Navajo section, and the Grand Canyon section. Along the Pacific margin, the Cascade-Sierra Mountains form a single province, divided into the Northern, Middle, and Southern Cascade Mountains and the Sierra Nevada. The Sierra Nevada and the Cascades are the principal high ranges west of the Basin and Range, and the Cascades include volcanic peaks.\n\nAlaska, the Aleutians, Hawaii, and the Continental Extremes\n\nThe Alaska Range is a relatively narrow mountain range in the southcentral region of the state, with Denali as its highest peak. Denali reaches 20,310 ft (6,190 m) and is the highest point in both the United States and North America. The Aleutian Islands form a volcanic arc that was formed by subduction-zone volcanism. Their peaks are steep and symmetrical; for example, the summit of Mount Vsevidof is the highest point on Umnak Island, one of the eastern Aleutian Islands.\n\nHawaii's landscape is entirely volcanic. Mauna Kea is one of the five shield volcanoes that form the Big Island. Its rise is partly hidden, since more than half of its height falls below the Pacific Ocean surface. Above the water, its peak is 13,803 feet (4,207 m) above sea level, making it the highest point in Hawaii. If height is measured from the seafloor rather than from sea level, Mauna Kea becomes the tallest mountain in the country.\n\nThe continent's extremes lie at opposite ends of the elevation scale. The lowest point on land in the United States is in Death Valley, California, where Badwater Basin is an endorheic basin, 282 feet (86 m) below sea level. Death Valley lies less than 85 miles from Mount Whitney, the highest point in the contiguous United States. Mount Whitney rises to 14,505 feet (4,421 m). Counting from the lowest point to the summit of Denali gives a total national elevation span of roughly 20,600 feet."
    },
    {
      "heading": "Geology and Tectonic History",
      "text": "The bedrock of the United States is a record of several continental assemblies and breakups, and its present landscape is the product of three main processes: the slow stability of ancient cores, episodic mountain-building, and the ongoing grinding of the Pacific margin. The oldest material lies in the north-central and northeastern parts of the country, where the Laurentian craton extends southward from Canada. In the United States, the exposed Precambrian crystalline rocks of the Canadian Shield appear mainly in the Adirondack Mountains of New York, the Upper Peninsula of Michigan, northern Wisconsin, and northern Minnesota. Across much of the rest of the interior, the crystalline basement is buried beneath younger sedimentary layers, forming the broad, gently tilted Interior Platform. These cratonic cores have been stable for hundreds of millions of years, which is why they rarely deform and why their thin soils and bare outcrops are so distinctive.\n\nMountain-building has repeatedly reshaped the margins of this old core. The Appalachian chain in the east developed through Paleozoic collisions between continental blocks, the final stage of which assembled the supercontinent Pangaea. Those mountains were once far higher than today, and erosion over hundreds of millions of years reduced them to the rounded ridges and valleys seen now. The Appalachian belt also left behind coal-bearing sedimentary sequences that later became important energy resources. In the west, a different sequence unfolded. The Laramide orogeny lifted the Rocky Mountains between roughly 80 and 35 million years ago. Unlike the thrust-belt style of the older Sevier deformation to the west, the Laramide event produced basement-cored uplifts, in which blocks of ancient crystalline rock were pushed upward along steep faults and flanked by deep sedimentary basins. Researchers generally link this deformation to a period when the oceanic plate beneath the western margin subducted at an unusually shallow angle, pushing deformation far inland. Subsequent Cenozoic uplift, extension in the Basin and Range, and volcanism created the younger ranges of the western Cordillera.\n\nThe Pacific coast is the most tectonically active part of the country, and it is defined by two contrasting boundaries. The San Andreas Fault, roughly 750 miles long, marks a transform boundary where the Pacific plate slides northwestward past the North American plate. Because the motion is largely horizontal, the fault produces repeated strike-slip earthquakes rather than building high mountains. Further north, the Cascadia subduction zone is a convergent boundary about 1,000 km long, where the small Juan de Fuca and Gorda plates dive eastward beneath the North American plate off the coast from northern California to Vancouver Island. Strain builds up on the locked interface and is released in sudden megathrust earthquakes. Geological evidence points to a magnitude 9 event in 1700 CE, and paleoseismic records suggest that such great earthquakes recur on average about every 500 to 550 years. The Mendocino triple junction off northern California, where the Pacific, North American, and Juan de Fuca plates meet, links the two systems.\n\nVolcanism has added to the country's geology in several separate settings. The Hawaiian islands were built by a mantle hotspot beneath the Pacific plate, which has moved northwestward over time, so the islands grow younger toward the southeast, and the island of Hawaiʻi remains volcanically active today. Yellowstone is a different kind of hotspot, positioned beneath the North American plate, which is moving southwestward over it; the resulting caldera system has produced several enormous eruptions in the last few million years, and it remains a region of geothermal activity. The Aleutian arc in Alaska records the subduction of the Pacific plate beneath the North American plate, and it has generated a chain of active volcanoes that stretches across the Alaska Peninsula and the Aleutian Islands.\n\nThese tectonic and volcanic processes also shaped the country's fossil-fuel endowment. Coal in the Appalachian and Illinois basins formed from Carboniferous swamp vegetation buried in subsiding basins during the Paleozoic. Petroleum and natural gas accumulated in sedimentary basins formed by the Laramide and earlier deformation, including the Permian Basin of Texas and New Mexico, the Rocky Mountain basins, and the Gulf Coast. Along the Alaskan margin, sedimentary basins on the North Slope and elsewhere hold substantial hydrocarbon reserves, and their distribution is closely tied to the subduction and terrane-accretion history that produced the Alaskan arc."
    },
    {
      "heading": "Rivers, Lakes, and Water Resources",
      "text": "The Mississippi–Missouri river system\n\nThe interior of the country drains through the river network centered on the Mississippi and its largest tributary, the Missouri. The Mississippi is the main stem of the largest drainage basin in the United States. The U.S. Army Corps of Engineers gives the basin an area of more than 1,245,000 square miles, with all or parts of 31 states and two Canadian provinces, and says it drains about 41 percent of the contiguous 48 states. The basin is often described as funnel-shaped, with its outlet at the Gulf of Mexico, and water from as far east as New York and as far west as Montana reaches the lower river. Near Baton Rouge, the average flow is roughly 593,000 cubic feet per second.\n\nThe Missouri, which rises in the Rocky Mountains of southwestern Montana, drains a semi-arid watershed of about 529,000 square miles that reaches into parts of ten states and two Canadian provinces. Although it enters the Mississippi north of St. Louis, it is slightly longer than the Mississippi above their confluence, and the combined system is commonly ranked among the longest river systems in the world. The Ohio River, another tributary, carries more water than the Missouri. Sources differ on exact lengths, so figures should be read as approximate.\n\nBecause the lower valley is flat and prone to flooding, engineering has long shaped the river. Floods in 1849 and 1850 led to national interest in control, and the 1927 flood inundated an area of about 26,000 square miles. Levees and other works followed, later organized under the Mississippi River and Tributaries Project. The river also carries sediment and dissolved nutrients from farmland to the Gulf, where nutrient loading contributes to a seasonal low-oxygen zone off the Louisiana coast, a problem associated with eutrophication.\n\nThe Great Lakes\n\nThe Great Lakes form the largest surface freshwater system in the world. They supply drinking water to more than 30 million people on both sides of the border, and their shipping lanes link the interior to the Atlantic through the St. Lawrence Seaway. Four of the five lakes are shared with Canada; Lake Michigan lies entirely within the United States.\n\nBinational governance dates to the Boundary Waters Treaty of 1909, which created the International Joint Commission to prevent and resolve disputes over shared waters. The two countries signed the Great Lakes Water Quality Agreement in 1972 to coordinate pollution control. Water-quantity rules are more recent. The Great Lakes–St. Lawrence River Basin Water Resources Compact was endorsed by the eight Great Lakes states and took effect on December 8, 2008, as both federal and state law. Its companion agreement, signed in 2005 with the premiers of Ontario and Quebec, is non-binding; its provisions are carried out by the states through the compact and by the provinces through their own legislation. The compact bans new or increased diversions of water outside the basin, with limited and tightly regulated exceptions, and it treats groundwater, surface water, and tributaries as a single system. Because the Canadian federal government and the provinces are not parties to the compact itself, commentators have discussed how the arrangement depends on continued cooperation, and recent trade disputes have raised questions about the durability of the shared-management model.\n\nThe Colorado River and western water allocation\n\nThe Colorado River is governed by a body of compacts, federal statutes, and court decisions known as the \"Law of the River.\" The 1922 Colorado River Compact divides the basin into an Upper Basin (Colorado, New Mexico, Utah, and Wyoming) and a Lower Basin (Arizona, California, and Nevada). It requires the Upper Basin not to deplete the river below a set volume over ten-year periods, and it is part of the framework for delivering water to Mexico under a 1944 treaty. The principal storage works are Hoover Dam and Lake Mead on the Lower Basin side and Glen Canyon Dam, completed in 1963, which forms Lake Powell on the Upper Basin side. Reservoir release rules adopted in 2007 governed Lake Powell and Lake Mead for nearly two decades.\n\nThe system has been under severe strain. By 2005, during the Millennium Drought, both reservoirs were about half empty. In 2026, the Bureau of Reclamation reduced planned releases from Lake Powell to Lake Mead, from 7.48 million acre-feet to 6 million acre-feet for the water year, to protect hydropower and infrastructure at Glen Canyon Dam. Lake Powell was about 25 percent full in late April 2026, and combined storage in the two reservoirs in mid-July fell to its lowest level since 1957. The post-2007 operating rules expired in 2026, and the seven basin states have not reached a consensus on how to share shortages. Some Lower Basin officials have argued that reduced deliveries violate the 1922 compact, which raises the prospect of interstate litigation, while federal planning documents set out operating guidelines for 2027–2028 and a longer decision framework.\n\nThe High Plains (Ogallala) aquifer\n\nWater in the semi-arid Great Plains is also drawn from underground. The High Plains aquifer, commonly called the Ogallala, lies beneath parts of eight states from South Dakota to Texas. Its development after the mid-twentieth century, especially with center-pivot irrigation, made the region one of the country's major irrigated agricultural areas, including large shares of the corn, wheat, and cotton grown there. Withdrawals have repeatedly exceeded natural recharge, which is slow in a dry climate, so water levels have fallen substantially in parts of western Kansas, the Texas Panhandle, and other irrigated zones. Local responses have included more efficient irrigation, crop changes, and state limits on pumping, though the rate of decline varies from place to place. Western water allocation generally follows the principle that earlier rights take precedence, which complicates efforts to reduce pumping collectively, a tension examined further in the discussion of water scarcity."
    },
    {
      "heading": "Climate and Weather Patterns",
      "text": "Climate types of the contiguous states\n\nThe contiguous states are commonly grouped into nine climate regions. The National Oceanic and Atmospheric Administration (NOAA) divides the contiguous US into nine climate regions, each a cluster of states with broadly similar weather. In the Köppen system, which classifies climate by temperature and precipitation patterns, the lower 48 span several main groups. The Southeast is typically humid subtropical: hot humid summers and mild but frosty winters, with precipitation spread across the year. The Pacific Northwest falls in the marine west coast type, where ocean winds bring mild winters and cool summers, and low clouds, fog, and drizzle are typical. Much of the interior West and the Great Plains is dry. Only the southern tip of Florida and Hawaii are tropical, and class A tropical climates are found in South Florida, Hawaii, Puerto Rico and the US Virgin Islands.\n\nAlaska does not fit the contiguous pattern. Its climate is largely subarctic, with a subpolar oceanic climate in the southeast (Alaska Panhandle), southwestern peninsula and Aleutian Islands, and a polar climate in the north.\n\nLarge-scale circulation drives these patterns. The primary drivers of weather in the contiguous United States are the seasonal change in the solar angle, the migration north–south of the subtropical highs, and the seasonal change in the position of the polar jet stream.\n\nThe 100th meridian and the arid–humid divide\n\nIn the nineteenth century, John Wesley Powell described an \"arid region\" as the land west of the 51-centimeter-per-year rainfall line, which closely tracked the 100th meridian. Along that belt, average annual rainfall fell from 61 centimeters on the eastern edge to 46 centimeters at the western edge.\n\nThe gradient has a physical cause. Moist air from the Gulf of Mexico typically reaches the 100th meridian and no farther, while the Rocky Mountains create a rain shadow to their east. In winter, the arid regions west of the 100th meridian are shielded from Pacific storm-related precipitation and are too far west to benefit from Atlantic storms. Modern analysis also finds that the gradient is driven by more than rainfall alone. Research by Seager and colleagues argues that the zonal variation of VPD acting alone creates a vast region of higher aridity in the interior west, where VPD refers to vapor pressure deficit, a measure of how strongly air pulls moisture from soil and plants. Their analysis of 1979–2016 data places the sharpest gradient near the 98th meridian rather than the 100th, and precipitation and relative humidity are the most significant contributors to the present gradient.\n\nStorms and regional hazards\n\nHurricanes form over warm Atlantic and Gulf waters and threaten the Atlantic and Gulf coasts, mainly from June through November. The central Great Plains, the corridor often called Tornado Alley, has the highest frequency of tornadoes in the country, especially in spring. Along the Pacific coast, atmospheric rivers, which are narrow corridors of concentrated water vapor, bring intense winter rain and mountain snow, and that snowpack supplies much of the water used in California and the Pacific Northwest.\n\nClimatic extremes\n\nThe contrast between states is sharp. Using 1971–2000 data, state-wide averages of annual temperatures range from a high of 70.7 degrees Fahrenheit (21.5 degrees Celsius) in Florida to a low of 26.6 °F (-3.0 °C) in Alaska. For precipitation, state-wide averages of annual rainfall plus snowfall range from a high of 63.7 inches (1618 millimetres) in Hawaii to a low of 9.5 inches (241 millimetres) in Nevada.\n\nAverages hide wide internal variation, especially in Alaska. Juneau averages over 50 inches (1,270 mm) of precipitation a year, while other areas in southeast Alaska receive over 275 inches (6,980 mm). Meanwhile, the northern side of the Seward Peninsula is a desert with less than 10 inches (250 mm) of precipitation annually.\n\nAverages also shift with the baseline period. NOAA's 1991–2020 normals put Florida at 73°F and Nevada at 52°F in annual mean temperature, which makes the gap between them smaller than in the older data. Recent years show the trend: Utah and Nevada recorded their warmest years on record at 4.3°F and 3.7°F above their 20th-century averages, respectively. In Hawaii, 2025 rainfall reached about 68 percent of normal (1991–2020)."
    },
    {
      "heading": "Ecosystems and Biodiversity",
      "text": "Major biomes\n\nBecause the country spans the tropics to the Arctic, its land cover is unusually varied. Deciduous temperate forest covers the eastern half of the contiguous states, extending from the Atlantic coast to the centre of the continent (The east coast, all the way to the center of the country, is also temperate deciduous forest.). West of the Mississippi, the central plains once supported a vast prairie. Trees are scarce there because the treeless condition is maintained by low precipitation, frequent fires, and grazing. Desert occupies the Southwest, where mountain ranges wring moisture out of the air and leave basins in their rain shadow; the Mojave and Sonoran deserts are the best-known examples (Deserts are frequently located on the downwind or lee side of mountain ranges, which create a rain shadow after prevailing winds drop their water content on the mountains. This is typical of the North American deserts, such as the Mohave and Sonoran deserts.). The Pacific Northwest contains coniferous forest, and in the far north, Alaska's interior and northern coast include boreal forest and tundra, where permafrost restricts plant growth to low vegetation.\n\nFlorida's southern peninsula, including the Everglades and the Florida Keys, contains subtropical and tropical habitats that have no equivalent on the mainland. Hawaii adds further range: its lowland wet forests are tropical, while its high summits support alpine grassland and cold, dry desert-like zones. The Hawaiian high shrublands, for instance, occupy the upper slopes of Haleakalā, Maui and are a tropical savanna-type ecoregion.\n\nBiodiversity hotspots and endemism\n\nHawaii is the country's clearest case of biodiversity-hotspot status and high endemism. Figures vary with the counting method. More than 90% of Hawaii's native species that live on land are endemic. When marine species are included, the share drops to just under half. Plants show a similar pattern, with 83% of its plant species being endemic to the state. Because island species evolved in isolation, endemism concentrates the risk: 55% of all documented global plant extinctions occurred on islands.\n\nThe Pacific Northwest, with its temperate rainforests and mountain ecosystems, and the southeastern forests, which include the Appalachian and coastal plain systems, hold many species found in few other places. These regions are discussed in terms of the freshwater and forest species that have restricted ranges, although the precise endemism counts for the mainland regions are not summarized here.\n\nSpecies of conservation concern and habitat loss\n\nHawaii's high endemism produces a high concentration of threatened species. While only comprising less than 1% of the U.S. land mass, Hawaiʻi contains 44% of the nation's endangered and threatened plant species. Habitat loss is severe in its dry forests: the Hawaiian dry forests have been seriously reduced due to habitat loss from commercial or agricultural development and the spread of invasive plant and animal species, and one source estimates that more than 90% of them have already disappeared.\n\nOn the mainland, habitat loss is most visible in grasslands, which have been converted to cropland and grazing. One western short-grass ecoregion is estimated to have habitat loss: 30.5%, while only about 5 percent of it is protected. Fragmentation from roads, cities, and farmland divides populations of wide-ranging species into smaller patches, which reduces genetic exchange and increases the risk of local extinction.\n\nInvasive species\n\nNon-native organisms are a major pressure on native ecosystems. More than 6,500 nonindigenous species are now established in the United States, posing risks to human and wildlife health, native plants and animals, and our valued ecosystems. Island ecosystems are especially exposed, since native species have few defences against predators and competitors they did not evolve with. On Guam, brown tree snakes have been implicated in the precipitous decline in native forest birds and the modern extinction of at least 10 species in Guam.\n\nIn freshwater systems, zebra and quagga mussels have transformed the Great Lakes. They devastate native species by stripping the food web of plankton, which has a cascading effect throughout the ecosystem. In the arid West, the invasive tamarisk, or salt cedar, consumes large volumes of water, reducing supplies for towns, farms, and hydropower. Estimates of the total annual cost of invasive species, including ecological and economic damage, exceed $120 billion, annually."
    },
    {
      "heading": "Indigenous Peoples and the Pre-Colonial Landscape",
      "text": "Archaeological evidence shows that people lived across the territory of the present United States well over 13,000 years ago, and some disputed sites are reported to be considerably older. By the time of European contact, the land held hundreds of distinct nations whose languages belonged to many language families, including Algonquian, Siouan, Iroquoian, Uto-Aztecan, and Athabaskan. Their societies ranged from small mobile bands of hunter-gatherers to farming towns and chiefdoms with monumental architecture, and no single cultural pattern covered the continent.\n\nThe most densely settled pre-contact society in the present-day United States was the Mississippian culture, which flourished in the Mississippi and Ohio river valleys and across the Southeast from roughly 800 to 1600 CE. Its largest center, Cahokia, near modern St. Louis, was the largest pre-Columbian settlement north of Mexico, and it covered nearly 1,600 ha and included some 120 mounds. The most prominent structure, Monks Mound, is the largest prehistoric earthwork in the Americas, covering over 5 ha and standing 30 m high. Population estimates for Cahokia's peak vary considerably. One source gives a population of 10,000–20,000 at its peak between 1050 and 1150, while others place the figure as high as 40,000. The city's economy rested on intensive cultivation of corn, beans, squash, and other crops, which allowed for large population concentrations in towns and villages. Its decline in the 14th century is usually linked to environmental stress; one account attributes it to deforestation and overhunting, and the site was largely abandoned by about 1400.\n\nIn the Southwest, the Ancestral Puebloan communities developed distinct regional branches, and they are known today chiefly for their masonry and cliff architecture. The National Park Service recognizes several branches, including the Kayenta, Little Colorado, Mesa Verde, Chaco, and Rio Grande groups. The people who built the cliff dwellings of Mesa Verde and the great houses of Chaco Canyon were subsistence farmers of corn, beans, and squash. The Chaco great houses were multistory structures, and they were built between 850 and 1150. Mesa Verde reached a peak population of more than 20,000 between about 1200 and 1250. Drought and food shortages, together with climate change, led many communities to abandon the region by 1300 and move south into present-day Arizona and New Mexico. Modern Pueblo peoples descend from these populations, and the great shuffling of populations on the landscape after A.D. 1300 insured that modern pueblo communities would be made up of multiple groups from widespread geographical origins.\n\nPre-contact peoples actively shaped the landscape. Farming supported dense settlement in river bottomlands, while in other regions Indigenous groups used controlled burning to maintain grasslands, savannas, and game habitat, and they built irrigation canals in the desert Southwest, as the Hohokam did in the Phoenix Basin. Long-distance exchange linked many of these societies. Cahokia was the hub of a trading network reaching to the Great Lakes and the Gulf Coast, and copper, marine shell, and other materials moved across the continent through similar networks. These practices produced stable, managed ecosystems and settlement patterns that European colonists later altered or displaced.\n\nIndigenous nations retain their political identities and legal standing. As of 2026, the federal government recognizes 575 federally recognized Tribes, or groups of Indigenous people that have a formally acknowledged government-to-government relationship with the United States. Earlier official counts were 574, and the most recent change came when Congress extended full recognition to the Lumbee Tribe of North Carolina in the fiscal 2026 defense authorization act. Roughly 40% of recognized tribes are in Alaska. Federal recognition carries limited sovereign immunity and powers of self-government, and the federal government also acknowledges a federal trust responsibility that rests on treaties, statutes, and court decisions. Tribal nations maintain their own courts and governments, and many also negotiate with state governments over gaming, land, water, and natural resources. Pending petitions from other groups seeking recognition show that the question of who qualifies remains open. Their relationship with federal and state authorities is shaped by the principle of sovereignty and by a long history of treaties, land cessions, and legal disputes."
    },
    {
      "heading": "Territorial Expansion and Settlement History",
      "text": "European settlement began along the Atlantic coast in the early seventeenth century, and by the mid-1700s Britain's thirteen North American colonies stretched in a narrow band from New England to Georgia. Their sense of a common political identity sharpened during the independence struggle, and the colonies declared independence in 1776. The 1783 peace settlement set the new republic's western limit at the Mississippi River. The states claimed the lands between the Mississippi and the Appalachians but did not administer most of them, and by 1802 those western claims had largely been ceded to the federal government or converted into new states. Vermont was admitted in 1791 after a period as an independent republic, and Florida was transferred from Spain in 1819 under the Adams–Onis Treaty.\n\nPurchases and Treaties, 1803–1853\n\nThe Louisiana Purchase of 1803 was the largest single addition. The United States bought the territory from France for $15 million, a deal that secured control of the Mississippi trade route and added roughly 828,000 square miles. Annexation of the Republic of Texas in 1845 and the Oregon Treaty with Britain in 1846 extended the country to the Pacific, and the Mexican–American War ended with the Treaty of Guadalupe Hidalgo in 1848. Under that treaty Mexico ceded about 525,000 square miles, including what became California, Nevada, Utah, and much of Arizona and New Mexico. The United States paid $15 million, and it also assumed certain claims of its citizens against Mexico.\n\nThe Gadsden Purchase of 1853 finished the modern southern boundary. Negotiated by James Gadsden under President Franklin Pierce, it paid $10 million for a strip of northern Mexican territory, the Mesilla Valley, which is now southern Arizona and southern New Mexico. Advocates of a southern transcontinental railroad, whose most practical route ran through this region, were a major motive. Sources differ on its size, with figures ranging from about 29,670 to roughly 55,000 square miles. The treaty also resolved disputes left unsettled by the 1848 treaty, and it is generally regarded as the last major addition to the contiguous United States.\n\nAlaska, Hawaii, and Overseas Acquisitions\n\nThe purchase of Alaska in 1867 came from Russia, which was reluctant to hold a remote territory that was hard to defend against Britain. Secretary of State William H. Seward agreed on a price of $7.2 million, roughly two cents an acre, on March 30, 1867. The Senate ratified the treaty on April 9, and the transfer took place on October 18. Critics mocked the purchase as \"Seward's Folly,\" but gold discoveries in the 1890s and later resource wealth changed that view. Alaska became a territory in 1912 and a state in 1959.\n\nHawaii followed a different path. American planters and businessmen overthrew Queen Liliuokalani in 1893 with the support of U.S. Marines, and President Grover Cleveland refused to annex the islands. After the Spanish–American War began in 1898, the value of Hawaii as a Pacific naval station grew. Because a treaty would have required a two-thirds Senate vote that could not be secured, the annexation was carried out by joint resolution, the Newlands Resolution, which required only a majority in each chamber. President William McKinley signed it on July 7, 1898, and the territory was formally created in 1900.\n\nThe Treaty of Paris of December 1898 ended the Spanish–American War. Spain relinquished Puerto Rico, Guam, and the Philippines to the United States, and Cuba became a de facto American protectorate. The Philippine–American War followed in the Philippines, and the eastern islands of Samoa were added in 1899. The Guano Act of 1856 also allowed the United States to claim small Pacific islands, which were later administered as unincorporated territories. These overseas acquisitions marked the start of an overseas empire, and their legal status as unincorporated territories remains a persistent question.\n\nWestward Movement and Indigenous Nations\n\nContinental expansion was driven by settlement, economic interest, and the ideology of Manifest Destiny, the belief that American settlement across the continent was preordained. Westward movement repeatedly displaced Indigenous nations. The Indian Removal Act of 1830 authorized the forced relocation of Southeastern nations west of the Mississippi, a process that produced the Trail of Tears. Treaties were frequently broken or renegotiated under pressure, and federal policy later shifted toward allotment of communal lands, most notably under the Dawes Act of 1887, which sharply reduced Indigenous land holdings. Similar dispossession affected Mexican citizens who remained in the ceded territories after 1848 and 1853.\n\nThe stabilization of the modern borders was thus a process of conquest, negotiation, and purchase over roughly a century. Settlement moved in waves of territorial organization, followed by statehood once population thresholds were met. The last of the contiguous states, Oklahoma, was admitted in 1907. Questions about the legitimacy of these acquisitions, and about the continuing sovereignty of tribal nations and the political status of overseas territories, remain part of the country's public debate."
    },
    {
      "heading": "Population, Settlement, and Urbanization",
      "text": "The 2020 decennial census counted 331,449,281 residents, a figure that serves as the benchmark for later official estimates. The Census Bureau's Vintage 2025 series put the population at 341,784,857 on July 1, 2025. That is an increase of about 1.8 million, or 0.5%, over the previous twelve months. Growth has slowed sharply, and the Bureau attributes the slowdown mainly to a decline in net international migration. Net international migration was roughly 1.3 million in 2024–2025, while natural change (births minus deaths) added about 519,000 people. The new estimate for 2025 is lower than the Census Bureau had implicitly projected a year earlier. The foreign-born share of residents was 15.2% in 2024.\n\nUrban and rural distribution\n\nThe Census Bureau defines urban areas by density rather than by municipal boundaries. An urban area must contain at least 2,000 housing units or a population of at least 5,000, and the designation \"rural\" covers any population, housing, and territory not included in an urban area. On this basis, the 2020 census classified 80.0% of the population as urban. Census-defined rural areas included 66.3 million residents, or 20 percent of the population. Metropolitan counties held about 285.6 million people, roughly 86% of the total, and the urban share within them was 87.1%, far above the 36% recorded in nonmetro counties.\n\nThe figure of about 83% that is often cited comes from a different series. The World Bank and UN urban series reports an urban population share of 83.5% for 2024. Because it uses different definitions, it cannot be compared directly with the census-based share.\n\nRegional shifts toward the South and West\n\nPopulation growth has been uneven across regions. All age groups in the South grew faster than in any other region from 2020 to 2025, primarily fueled by outlying metro counties. Between April 2020 and July 2025, the national population rose by 3.1%, while the Northeast grew by only 0.7%, so its share of the total fell. Texas grew from 29.1 million to 31.7 million, Florida from 21.5 million to 23.5 million, and North Carolina and Georgia also added large numbers of residents. By contrast, California's population declined slightly, and New York's fell from 20.2 million to 20.0 million over the same period. The shift is therefore a movement toward the South and the interior West, not only a rise in the West overall. The Midwest's share has also declined, as the regional figures show weaker growth than the national average.\n\nAge structure, median age, and fertility\n\nThe population is aging. The median age was 39.4 in 2025, up from 39.2 in 2024, and in 2001 it had been 35.6. Between 2020 and 2025, the population aged 65 and over grew by 16.2%, to about 64.6 million, while the population under 18 fell by 2.4%, to about 72.0 million. The sex ratio among older adults is also shifting: by 2025 the ratio of men to women aged 65 and older had risen to 81.6, reflecting narrowing mortality gaps.\n\nFertility is a major factor in projected growth. The Census Bureau projects a total fertility rate of 1.63 in 2025, gradually decreasing to 1.60 by 2050. Declines are concentrated among younger women, while rates for women aged 30 and over are projected to rise. The Congressional Budget Office now projects the population to grow from 350 million in 2025 to 367 million in 2055, a downward revision from its earlier outlook, reflecting lower fertility and net immigration. An older population with fewer births means slower growth and a larger share of residents at retirement age, which has consequences for the labor-market and for public pension and health systems."
    },
    {
      "heading": "Government and Constitutional System",
      "text": "The United States is governed under a single written constitution that was drafted in Philadelphia in 1787 and put into operation in 1789, after the required number of states had approved it. The document sets up a national government with enumerated powers, divides that government among three branches, and leaves a broad range of authority with the states. The structure has been amended only through a formal procedure, and its meaning has been shaped over two centuries by courts, Congress, and presidents.\n\nThe Constitution, the Bill of Rights, and Amendment\n\nThe Constitution was written without a list of individual rights. Delegates at the 1787 convention rejected a proposal to add one, and several states ratified anyway. The first ten amendments were written in response to objections raised by Anti-Federalists during the often bitter 1787–88 ratification debate. Ratification in some states depended on a promise that such protections would follow. Ratification efforts in New York and Virginia only succeeded after the Federalists promised to add one.\n\nJames Madison led the drafting work in the First Congress. Rather than inserting changes into the body of the original text, Congress attached them as supplementary articles. On 25 September 1789 Congress sent twelve proposed articles to the states, and ten of them were adopted on 15 December 1791 as the Bill of Rights, the First through Tenth Amendments. Contrary to Madison's proposal that the proposed amendments be incorporated into the main body of the Constitution, they were proposed as supplemental additions. Articles Three through Twelve were ratified as additions to the Constitution on December 15, 1791, and became Amendments One through Ten.\n\nArticle V sets out two routes for proposing an amendment: a two-thirds vote in both chambers of Congress, or a convention called at the request of two-thirds of the state legislatures. Of the two options, the national convention has never been used. Ratification requires approval by three-fourths of the states, either through their legislatures or through state conventions. Since the Bill of Rights, the Constitution has been amended 17 more times, the most recent being the 27th Amendment, which was certified in 1992 and concerns congressional pay.\n\nSeparation of Powers and the Bicameral Congress\n\nThe Constitution assigns legislative power to Congress in Article I, executive power to the president in Article II, and judicial power to the federal courts in Article III. This arrangement is commonly described as a separation of powers within a presidential-system, in which the president is elected separately from the legislature and does not depend on its confidence to remain in office. Each branch holds tools to limit the others: the president can veto legislation, Congress can override a veto with a two-thirds vote in each chamber, the Senate must confirm major executive and judicial appointments, and Congress can impeach and remove federal officers.\n\nCongress is bicameral. The House of Representatives is apportioned by population among the states, with its members elected from districts, while the Senate gives each state two senators regardless of size. This design reflects the compromise reached at the 1787 convention, which balanced populous and less populous states. Because both chambers must pass a bill and the president must sign it or fail to veto it, lawmaking requires agreement across institutions that often have different constituencies and terms.\n\nFederalism and the States\n\nThe Tenth Amendment provides that powers the Constitution neither gives to the national government nor forbids to the states belong to the states or to the people. In practice, the 50 states each have their own constitution, legislature, governor, and court system, and they regulate areas such as family law, most criminal law, education, and many aspects of land use. The national government's powers rest on specific grants, including the power to regulate interstate commerce and to tax and spend for the general welfare, and federal courts and agencies operate alongside state institutions rather than replacing them. The balance between the two levels has shifted repeatedly, and debates over that balance remain central to American politics. The federalism system is therefore a continuing negotiation rather than a fixed division.\n\nThe Supreme Court, Judicial Review, and the Federal Courts\n\nArticle III vests the judicial power in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish. Congress decides how the lower federal courts are organized, so the number of district courts and appeals courts has changed over time. Federal judges serve during good behaviour and are protected from salary reductions while in office. The Judges, both of the supreme and inferior Courts, shall hold their Offices during good Behaviour, which gives them lifetime tenure in practice, subject to impeachment.\n\nThe power of the courts to strike down statutes was not stated in the text. The Constitution does not expressly grant the federal courts the power to declare government actions unconstitutional. That authority was established in Marbury v. Madison (1803), in which Chief Justice John Marshall held that a provision of the Judiciary Act of 1789 extended the Court's original jurisdiction beyond what Article III allowed, and therefore was void. It was the first case in which the Supreme Court invalidated a law passed by Congress. The decision made judicial-review a central feature of the system, and it allowed the courts to act as a check on both Congress and the president. The Supreme Court now possessed the ultimate check: power to review actions of both legislative and executive branches and invalidate them if they ran contrary to the Constitution.\n\nThe Supreme Court has had nine justices since 1869, though the number was set by Congress and not by the Constitution. Below the Supreme Court sit ninety-four district courts, thirteen courts of appeals, and specialized courts. Cases generally move upward from district courts to the appeals courts and then, if the Supreme Court grants review, to the nation's highest court, which decides which constitutional and federal questions it will take up."
    },
    {
      "heading": "Economy and Natural Resources",
      "text": "Size and sectoral composition\n\nBy output, the United States has the largest national economy in the world, and statistical estimates place its lead over China at roughly 11 trillion dollars. Its share of world output fell to about 21 percent around 2011 before recovering to roughly 26 percent, which is why the figure is often cited as a quarter of the global total.\n\nServices are the largest part of the structure. Depending on the dataset and how categories are drawn, the sector accounts for roughly 77 to 83 percent of value added. One BEA-based breakdown for late 2025 put services near 83 percent, industry at about 16 percent, and agriculture below 1 percent. Industry, which covers manufacturing, construction, mining, and utilities, once exceeded 35 percent of output in the mid-1950s. Within services, real estate and rental activity was the single largest contributor in 2025, followed by professional and business services and government.\n\nManufacturing remains large in high-value sectors such as aerospace, chemicals, machinery, and semiconductors. Technology, including software, cloud computing, and chip design, is a major source of private investment and exports, and it is concentrated in a small number of metropolitan clusters.\n\nAgriculture and agricultural regions\n\nAgriculture contributes only a small share of output but is internationally significant. The 2022 Census of Agriculture counted about 1.9 million farms, and the country is a net exporter of food. The Great Plains form a broad, flat belt of cropland between the Great Lakes and the Rocky Mountains. Within it, the wetter eastern half is the Corn Belt, where corn and soybeans dominate, while the drier western half specializes in wheat. Irrigated fruit, vegetable, and nut production is concentrated in California's Central Valley.\n\nCorn is the clearest case of export orientation. The country is the world's largest producer, consumer, and exporter of the grain, and it typically sends out between 10 and 20 percent of its crop. Iowa and Illinois together account for about one-third of the national harvest, and the leading foreign buyers include Mexico, China, Japan, and Colombia. Wheat exports were projected to reach around 42 to 44 percent of national production in the mid-2020s. Regional export profiles differ: the Midwest ships oilseeds and grain, the West Coast ships fruit, nuts, and vegetables, and the Southeast ships cotton, peanuts, rice, and poultry. Iowa, Illinois, and Minnesota send grain and soybeans down the Mississippi, which serves as the main agricultural export corridor.\n\nEnergy resources\n\nFossil fuels supply most of the country's primary energy. In 2025, total energy production reached a record 107 quadrillion British thermal units, a rise of 3.4 percent over 2024 and the fourth consecutive annual record. Natural gas has been the largest domestic energy source since 2011, and dry gas output reached a record 39 trillion cubic feet, with most growth in the Appalachian, Permian, and Haynesville regions. Crude oil output also set a record, at 13.6 million barrels per day, and most of the gain came from the Permian Basin of western Texas and southeastern New Mexico. Crude oil accounted for about a quarter of domestic production, and the country remains the largest crude producer in the world. Coal supplied about 10 percent of domestic production in 2025.\n\nCoal's place in the energy mix has changed sharply. Its share of total energy consumption fell from about 37 percent in 1950 to about 9 percent in 2025, mainly because power generators switched to other fuels. The gas-fired share of electricity now exceeds coal's, and in 2025 natural gas produced about 41 percent of utility-scale electricity, nuclear about 18 percent, coal about 17 percent, and renewable sources about 24 percent. Renewable production reached a record in 2025, growing for a fifth consecutive year, with solar and wind generation setting their own records as new plants came online. Renewables still represent only around a tenth of total primary energy, and the U.S. has been a net energy exporter since 2019.\n\nThe dollar, the Federal Reserve, and international trade\n\nThe U.S. dollar is the dominant reserve currency of the global system. It is the main currency used to invoice international trade, to settle foreign-exchange transactions, and to hold central bank reserves. This status lowers borrowing costs for the government and gives American monetary decisions unusual influence over global financial conditions.\n\nThe Federal Reserve System, created by the Federal Reserve Act of 1913, consists of a Board of Governors in Washington and twelve regional Reserve Banks. Congress has directed it to pursue maximum employment and stable prices, and it pursues those goals mainly through its target for short-term interest rates and open-market operations. Its decisions affect exchange rates, credit conditions, and asset prices worldwide.\n\nIn international trade, the country is among the largest importers and exporters of goods and services. It typically runs a deficit in goods and a surplus in services. It is a founding contracting party to the General Agreement on Tariffs and Trade and a member of the World Trade Organization, and it is a party to the USMCA with Canada and Mexico. Tariff policy has been an active area of change in recent years, which has made trade relations a recurring focus of domestic and diplomatic debate."
    },
    {
      "heading": "Culture, Language, and Religion",
      "text": "Language\n\nEnglish is the dominant language of public life, but the United States has no long-standing federal official-language designation. A 2025 executive order made English the official language of the federal government, and 32 out of 50 states have English as an official language in state law. ACS 2024 estimates put English-only speakers at home at about 247.7 million people (~77%). The remainder is more varied. Of 316,142,560 United States residents aged 5 and over, 70,375,520 speak a language other than English at home. That is 22.3 percent.\n\nSpanish is by far the most common of those languages. Spanish has roughly 45 million speakers (~14% of the population) at home, and in 2019 it was the non-English language of 62% of such households. Chinese, Tagalog, Vietnamese, Arabic and French form the next tier. At least 350 different languages are spoken in U.S. homes, according to a Census Bureau report, and that count includes roughly 150 Native North American languages. Many of these Indigenous languages are endangered, with a small number of remaining speakers, often elderly, in each community.\n\nBilingualism has not eroded English proficiency among immigrants in the way some assume. Across most age groups, the majority of people who speak a language other than English at home still speak English very well. In 2018–2022, 61.0% of Spanish speakers, 48.2% of Chinese speakers, and 69.8% of Tagalog speakers reported speaking English very well. The number of households using a non-English language grew threefold after 1980, a trend driven largely by immigration.\n\nReligion\n\nThe United States is predominantly Christian, although the share has fallen. The 2023–24 Religious Landscape Study finds that 62% of U.S. adults identify as Christians. That figure is well below the 78% recorded in 2007 and 71% in 2014. Since 2019, however, the Christian share of the adult population has been relatively stable, hovering between 60% and 64%. Protestants make up about 40% of adults and Catholics about 19%. Adherents of religions other than Christianity have grown in number but remain a small share, about seven percent. Two percent of adults are Jewish, and one percent each are Muslim, Buddhist or Hindu. About 29% of adults are religiously unaffiliated, a category that includes atheists, agnostics and people who report \"nothing in particular.\"\n\nReligious patterns vary by region and generation. Christians make up 68% of adults in the South, the most religious region, while in the West the figure is only 55%, with 35% of residents unaffiliated. The youngest adults are far less likely than the oldest to identify as Christian, with 46 percent against 80 percent. Immigrants are themselves mostly Christian, but a quarter of foreign-born U.S. adults claim no religion.\n\nThe First Amendment, ratified in 1791, protects religion through the Establishment and Free Exercise Clauses. The establishment clause bars the federal government from creating a national church or favoring one faith over another. The free exercise clause protects the right to practice any faith, or none. The Religion Clauses apply to Congress in the text of the provision, and to the states by incorporation through the Fourteenth Amendment. Free exercise is not unlimited: the government may limit religious practice when it violates general laws that apply to everyone. The two clauses can pull against each other. In Engel v. Vitale (1962), the Supreme Court held that prayers in public schools violated the Establishment Clause, even when they were nondenominational and not required to be recited.\n\nCultural Contributions and Immigrant Influence\n\nAmerican music has had worldwide reach. Jazz emerged in the early twentieth century from African American communities, especially in New Orleans, and it was followed by blues, country, gospel, rock and roll, soul and, from the 1970s, hip hop, which took shape in the Bronx. Literature includes the works of Mark Twain, Herman Melville, William Faulkner and Toni Morrison. Film became a major export through Hollywood, centered in Los Angeles, whose studio system shaped global cinema in the twentieth century. Broadway in New York is the country's best-known center of theatre and musical productions. In the visual arts, the nineteenth-century Hudson River School painted American landscapes, Abstract Expressionism led by Jackson Pollock arose in the mid-twentieth century, and Pop art associated with Andy Warhol emerged in the 1960s.\n\nSuccessive waves of immigrants, including German and Irish settlers in the nineteenth century and later Italian, Eastern European Jewish, Chinese, Mexican, Caribbean and Asian communities, have shaped American food and festivals. Tex-Mex cuisine, Italian-American dishes such as the New York-style pizza, and Chinese-American restaurant cooking are established parts of everyday eating. Cities hold Chinese New Year parades, Irish-American and Hispanic cultural festivals, and Juneteenth, a commemoration of the end of slavery that became a federal holiday in 2021."
    },
    {
      "heading": "Education, Science, and Research",
      "text": "Schooling and higher education\n\nBecause federalism leaves most education policy to the states, the United States has no single national school system. Most curriculum benchmarks and graduation rules come from state governments, while local districts handle daily operations. The system is a network of state, local, public, private, and postsecondary bodies rather than a centrally administered national school model. States establish most school standards and graduation rules, local education agencies operate schools, and colleges and universities retain wide institutional authority.\n\nCompulsory attendance laws generally keep children in school until about 16, and until 18 in some states. Education is mandatory until the age of 16 (18 in some states). The shorthand K–12 covers the span from kindergarten through twelfth grade. Within that span, schooling is typically organized as elementary school, middle or junior high school, and high school.\n\nBeyond high school, the postsecondary sector includes community colleges, state/public universities, private institutions, vocational/technical schools, and online universities. Credentials range from certificates and two-year associate degrees to four-year bachelor's degrees, master's programs, and research doctorates. According to the National Center for Education Statistics, 66.2% of high school graduates enrolled in higher education institutions in 2021. A subset of universities, mostly large public flagships and elite private institutions, combines undergraduate teaching with doctoral training and federally funded laboratory research.\n\nResearch spending and its sources\n\nTotal spending on research and experimental development reached $937 billion in 2023, with $138 billion for basic research, $174 billion for applied research, and $625 billion for experimental development. Federal statistics estimate that spending rose to $993 billion for 2024. Measured against the economy, the Organisation for Economic Co-operation and Development (OECD) figure for 2023 is 3.4% of GDP, amounting to $823.4 billion. Several smaller economies spend a larger share: Israel spent $28.3 billion on research and development (R&D) in 2023 to reach 6.3% of GDP, and South Korea falls next in line, with an R&D intensity of 5% of GDP.\n\nThe funding mix has shifted. The ratio of business-funded R&D to GDP was 1.70% in 2012 and 2.59% in 2022. Federal support has moved the other way: federally funded R&D peaked as a share of GDP in 1964, when federal funding accounted for 1.86% of GDP and 67% of all domestic R&D. By 2022, federally funded R&D was 0.63% of GDP and 18% of domestic R&D.\n\nNational laboratories\n\nA network of federal laboratories, most of them overseen by the Department of Energy, carries out research in physics, materials science, energy, and national security. Their presence is visible in regional statistics. The Bureau of Economic Analysis reported that R&D as a share of each state's gross domestic product ranged from 0.3 percent in Louisiana and Wyoming to 6.3 percent in New Mexico, home to federally funded Los Alamos National Laboratory and Sandia National Laboratories. Many of these facilities are operated by contractors, including universities, which links them closely to academic research.\n\nNobel Prizes and scientific output\n\nMeasured by Nobel Prizes, the country has the largest total of any nation. A Wikipedia compilation, based on the Nobel committee's own country attributions, lists 425 (428) laureates and prizes for the United States, well ahead of the United Kingdom with 144 (145). Totals differ across tallies because the Nobel committee's country attributions depend on each laureate's affiliation, citizenship, or birthplace; one ranking that counts differently gives a total of 383 winners. A substantial share of these laureates came from abroad: around 29% of them are immigrants from other nations.\n\nBeyond prizes, American universities and research institutions produce a large share of highly cited scientific papers and patents, and a significant share of the world's doctoral training in the sciences takes place within them. The relationship between this output and public funding remains central to policy debates about research priorities.\n\nTechnologies with American origins\n\nSeveral foundational technologies emerged from American research. The ARPANET, funded by the Defense Advanced Research Projects Agency, began operating in 1969 and used packet switching to link research computers; its protocols evolved into the internet that later became a commercial system in the 1990s. The World Wide Web, by contrast, was developed at CERN in Switzerland, so the web and the internet have different origins.\n\nThe semiconductor industry also grew out of American work. Jack Kilby at Texas Instruments and Robert Noyce at Fairchild Semiconductor independently developed integrated circuits in 1958 and 1959. Their commercial ecosystem concentrated in the San Francisco Bay Area, where Silicon Valley combined research universities, venture capital, and a dense network of start-up firms. Similar ecosystems in Boston, Austin, and Seattle have since formed around university research and industry clusters."
    },
    {
      "heading": "Infrastructure and Transportation",
      "text": "Highways and the automobile system\n\nThe road network rests on the Interstate Highway System, which was authorized by a single 1956 statute. The project grew out of the wartime experience of a future president, who had admired Germany's high-speed roads while stationed there Eisenhower had been stationed in Germany, where he had been impressed by the network of high-speed roads known as the Reichsautobahnen. The 1956 law set the planned length at 41,000 miles, and it tied the federal share of costs to motor-vehicle taxes placed in a dedicated fund, so the program was meant to pay for itself Revenue from the Federal gas and other motor-vehicle user taxes was credited to the Highway Trust Fund to pay the Federal share of interstate and all other federal-aid highway projects. In this way, the Act guaranteed construction of all segments of the system on a \"pay-as-you-go\" basis. The network now runs well beyond that original figure, spanning more than 48,000 miles (77,000 km) by the early 21st century.\n\nThe highways carry a disproportionate share of national travel. Although they make up only about one percent of the road network, they handle roughly a quarter of vehicle traffic. Historians also argue that the system reinforced car dependence: by draining traffic and investment from passenger railroads and downtown commercial districts, the interstates locked in an automobile-centered way of life. Below the interstate level, U.S. numbered highways, state routes, and county roads supply the regional road network, and many rural and suburban communities depend almost entirely on them.\n\nFreight and passenger rail\n\nThe country's rail system is dominated by private freight carriers. Six Class I railroads operate today, and Class I railroads account for around 67% of freight rail mileage, 87% of employees and 94% of revenue. Freight rail carries a large share of bulk goods, including coal, grain, chemicals, and intermodal containers. Freight railroads account for roughly 40% of U.S. long-distance freight volume (measured by ton-miles)—more than any other mode of transportation. The network is mostly privately owned, and passenger service is marginal. Amtrak owns 623 route miles (primarily in the Northeast), and intercity passenger trains generally share track with freight, which limits their speed. Proposals for high-speed rail have advanced slowly.\n\nRail geography is concentrated in a few hubs. Chicago is the nation's busiest rail hub. All six U.S. Class I railroads operate there, which makes the city a central interchange for goods moving between the coasts and the interior.\n\nPorts, rivers, and air hubs\n\nSeaports handle the country's maritime trade. Major container gateways include the Los Angeles and Long Beach complex on the Pacific, the New York and New Jersey harbor on the Atlantic, and Savannah and Houston on the Atlantic and Gulf coasts. Inland waterways supplement the coastal ports. The Mississippi system carries grain, petroleum products, and coal, with the ports of the lower river, especially south of New Orleans, handling large volumes of bulk export cargo.\n\nAir transport is organized around large hub airports operated by major airlines. Atlanta, Chicago O'Hare, Dallas–Fort Worth, and Denver are among the busiest, and they connect domestic cities with international routes. Air cargo is concentrated at a smaller number of airports, which handle time-sensitive freight and parcels.\n\nElectric grid and pipelines\n\nThe electrical system is not one national grid. The contiguous United States is divided into two large alternating-current systems, along with a separate system in Texas. The two major interconnections are the Eastern Interconnection and the Western Interconnection. The two were first made to run in synchrony in 1967 engineers activated links that allowed the giant Eastern and Western Interconnections to operate in synchrony. Power moves between them through direct-current ties, which avoid the need for the systems to share frequency. The Western system is tied to the Eastern one at several points, while the Texas grid is tied to the Eastern Interconnection at two points, and also has ties to non-NERC systems in Mexico.\n\nTexas keeps its system separate largely for political reasons. By not crossing state lines, the synchronous power grid is in most respects not subject to federal (Federal Energy Regulatory Commission) regulation. The 2021 winter storm exposed the cost of that isolation, and many people attributed the state's electricity woes to the lack of significant links to the eastern and western power systems. Proposals to connect the Texas grid to the wider system have been debated since.\n\nOil and gas move through a dense pipeline network. Natural gas is carried from producing regions such as the Gulf Coast and the Appalachian and Permian basins toward population centers, while refined petroleum products travel by long-distance product lines to coastal terminals and the Northeast. Pipelines are typically regulated and operated in regional segments rather than as a single national system.\n\nTelecommunications and broadband\n\nBroadband networks combine fiber-optic lines, cable television systems, digital subscriber line service over copper, fixed wireless, and satellite links. Urban and suburban areas are usually served by several providers, while rural regions often have one or none. Low population density means that the cost of stringing fiber or towers is spread across fewer customers, which makes extension of service expensive and reduces commercial incentives. Mountainous and remote terrain, including parts of the West and Alaska, adds further engineering costs. Public programs, including federal universal service support and the broadband grants created under the 2021 infrastructure law, aim to narrow the gap, but the rollout has been slow and the definition of adequate service has been contested."
    },
    {
      "heading": "Health, Healthcare, and Public Health",
      "text": "Life expectancy and mortality\n\nFederal data for 2024 put average life expectancy at birth at 79.0 years, a gain of 0.6 year over 2023. The age-adjusted death rate fell 3.8%, from 750.5 deaths per 100,000 standard population in 2023 to 722.1 in 2024. Women's life expectancy rose from 81.1 to 81.4 years, and men's rose from 75.8 to 76.5 years, so the gap between the sexes narrowed to just under five years. There were 3,072,666 resident deaths in the U.S. in 2024, 18,298 fewer than in 2023.\n\nThe leading causes of death have changed little from year to year. Heart disease, cancer, and unintentional injuries remained the top three causes. The 10 leading causes accounted for 70.9% of all deaths in the United States. In absolute terms, heart disease caused 683,037 deaths, cancer caused 619,812 deaths and unintentional injury resulted in 196,488 deaths. Stroke, chronic lower respiratory disease, Alzheimer's disease, diabetes, kidney disease, chronic liver disease, and suicide complete the list. Suicide became the 10th leading cause of death in 2024. Infant mortality did not change significantly, moving from 560.2 to 552.5 deaths per 100,000 live births. Death rates were highest among males, older adults, and Black people, and the Black death rate remained above that of all other groups.\n\nHealth insurance and the cost of care\n\nThe United States spends more on health care than any comparable country. In 2024, the U.S. spent 18 percent of gross domestic product on health care, nearly twice as much as the average OECD country, and among the highest rates in the world. National health expenditure reached $4.8 trillion in 2023, and the health share of GDP was 17.6% in 2023, up from 17.3% the year before.\n\nFinancing is split among public programs, employer and private coverage, and households. Government programs account for the largest share. The federal government is the largest sponsor of health care expenditures ($1.7 trillion and a 31 percent share in 2024), a total that includes the federal share of Medicaid and Medicare. Out-of-pocket spending is smaller but significant: out-of-pocket spending was $557 billion (11.0% of total HCE) in 2024, excluding premiums.\n\nCoverage estimates vary by source and year. A Congressional Research Service analysis reports that about 8.2% of the U.S. population was uninsured in 2024, while a Congressional Budget Office projection cited by a health systems database puts the figure at 7.7 percent, or 26 million. The Commonwealth Fund estimates about 27 million people. Being insured does not guarantee affordable care: 9 percent of adults were uninsured, 12 percent had a gap in coverage over the past year, and 23 percent were underinsured. The result, according to the Commonwealth Fund, is that people are far more likely to forgo needed care because of costs than people in peer countries. Coverage gaps are also uneven: uninsured rates have been higher in the South and West than in the Northeast and Midwest, and higher still among lower-income adults.\n\nHealth care is regulated at both federal and state levels. State decisions on insurance eligibility, particularly Medicaid expansion, shape local coverage rates.\n\nPublic health institutions and epidemics\n\nThe Centers for Disease Control and Prevention (CDC) and its National Center for Health Statistics compile mortality data. Their national figures are built using data collected by NCHS from death certificates filed in all 50 states and the District of Columbia. Surveillance of infectious disease and outbreak response is shared among federal agencies and state and local health departments.\n\nThe COVID-19 pandemic left a clear mark on the mortality record. It ranked among the leading causes in 2023 but has since receded. COVID-19, the 10th leading cause of death in 2023, dropped to the 15th leading cause in 2024. The pandemic also reduced life expectancy in 2020 and 2021, and the subsequent recovery in 2023 and 2024 is partly a return from those losses. Overdose deaths, which had been a major driver of recent mortality, also declined in 2024, according to the NCHS release.\n\nChronic disease, obesity, and regional variation\n\nMost deaths in the population are now linked to chronic conditions rather than infectious disease. Heart disease and cancer alone account for more than 40 percent of deaths. Heart disease kills more Americans than any other cause, accounting for roughly 22% of deaths in 2024. Among its main risk factors are high blood pressure, type 2 diabetes, and prediabetes. Diabetes itself caused 94,382 deaths in 2024, and kidney and liver disease together caused more than 100,000.\n\nObesity is widespread, with roughly two in five American adults classified as obese in recent national surveys, and it contributes to heart disease, diabetes, and several cancers. Rates of chronic disease and of premature death vary by state, race, ethnicity, and income. Heart disease is the leading cause of death in 41 states, and cancer leads in most of the rest, while Alzheimer's disease ranks among the top five causes in 11 states. These patterns track differences in income, access to care, and the prevalence of risk factors across regions."
    },
    {
      "heading": "Foreign Relations and Global Role",
      "text": "The United States takes part in the multilateral system created after 1945 and has been a founding member of several of its central bodies. It signed the United Nations Charter in 1945 and holds one of the five permanent seats on the UN Security Council, which gives it a veto over substantive resolutions. It also helped build the postwar financial order: the International Monetary Fund and the World Bank emerged from the 1944 Bretton Woods conference. Its engagement is uneven, however. It is not a party to the International Criminal Court's founding treaty, and it ended its acceptance of compulsory jurisdiction of the International Court of Justice in 1986. Its membership in UN human rights bodies has also been intermittent, with withdrawals and returns over the past decades.\n\nSecurity commitments form the second pillar. On July 25, 1949, the United States officially joined the treaty, becoming one of NATO's 12 founding members. The alliance rests on collective defense: under Article 5, each party must respond to an armed attack on another by taking \"such action as it deems necessary,\" which may but need not involve force. That discretion means Congress has retained a role in deciding the American response. NATO has invoked Article 5 only once in its history, the day after the September 11, 2001 attacks.\n\nThe forward military presence is extensive and its size depends on how it is counted. A Congressional Research Service review found approximately 67,200 active-duty servicemembers permanently assigned to overseas bases in Europe as of March 2024, with the largest contingents in Germany, Italy and the United Kingdom. In the Indo-Pacific, approximately 81,000 active-duty servicemembers were permanently assigned to overseas bases, with the largest number in Japan and South Korea. Counting all deployments, the Pentagon's Defense Manpower Data Center reported more than 171,500 active-duty personnel stationed in foreign countries as of June 2025. Estimates of the number of installations vary widely, and the figure most often cited, about 750 bases in some 80 countries, comes from non-official tallies. Definitions also differ: one count treats military installations larger than 4 hectares (10 acres) or worth more than $10 million as \"large\" bases, a category that accounts for about 60 percent of the total.\n\nTrade relations are governed by a mix of multilateral and bilateral instruments. The United States was an original signatory of the General Agreement on Tariffs and Trade in 1947 and has belonged to the World Trade Organization since its creation in 1995. Its most significant regional agreement is the United States–Mexico–Canada Agreement. The agreement entered into force on July 1, 2020, after Congress approved implementing legislation in December 2019. Unusually for a US trade pact, it includes a joint review clause. At the first review on July 1, 2026, the United States declined to confirm its intention to extend the agreement for an additional 16-year period. Canada and Mexico affirmed their support for renewing the agreement. Because no extension was agreed, annual joint reviews will proceed until the parties either agree to an extension or the agreement expires on July 1, 2036. All current USMCA rights and obligations, including preferential tariffs, rules of origin, and investment protections, remain fully operative.\n\nBeyond formal institutions, the country's influence rests on the dollar's central role in international finance, the reach of its alliance network in Europe and Asia, and the global diffusion of its language, technology and cultural output. Its approach to international law combines selective treaty ratification with reliance on domestic law. It has signed but not ratified several major human rights conventions, and its courts and executive branch regularly engage with international norms through bilateral and multilateral channels rather than through the binding jurisdiction of international tribunals."
    },
    {
      "heading": "Environmental Policy and Public Lands",
      "text": "Federal land ownership\n\nThe federal government owns a large share of the national territory. The Congressional Research Service estimates that it owns and manages roughly 640 million acres of land in the United States, or roughly 28% of the 2.27 billion total land acres. Other compilations report slightly lower figures, with one putting the holding at around 620 million acres (about 27 percent). The distribution is highly uneven. Federal land ownership is concentrated in Alaska (60.8%) and 11 coterminous western states (45.9%), in contrast with other states (4.1%). Nevada has the highest share within any state, at about 80%, while Connecticut and Iowa have the lowest, at 0.3%. Four agencies administer most of this land: the National Park Service, the Fish and Wildlife Service, the Bureau of Land Management, and the Forest Service. A fifth agency, the Department of Defense, administered 8.4 million acres in the United States, about 1% of all federal land in the United States.\n\nNational parks and protected areas\n\nThe National Park Service was created in 1916 to manage the growing number of park units established by Congress and monuments proclaimed by the President. The system now comprises 433 units covering about 85 million acres, but only 63 of them carry the \"National Park\" designation. The National Park System covers 85 million acres and comprises 433 sites, including 139 historical parks or sites, 87 national monuments, 63 national parks, 31 national memorials, 25 battlefields or military parks, and 88 otherwise designated national park units. Most NPS land lies in Alaska, where about two-thirds of the lands (52.5 million acres, or 65.6%) are in Alaska. The parks drew heavy use, with more than 330 million people visiting national parks in 2024.\n\nAir and water regulation\n\nFederal environmental regulation expanded sharply in the early 1970s. The Environmental Protection Agency was established in 1970, and like the Clean Air Act (1970) and the Endangered Species Act (1973), the CWA reflected Americans' growing concern about the environment. Water policy began earlier. The Federal Water Pollution Control Act of 1948 was the first major U.S. law to address water pollution. Its weak, state-centred enforcement led to the 1972 amendments, which made it unlawful for any person to discharge any pollutant from a point source into navigable waters, unless a permit was obtained under its provisions. The amendments also funded the construction of sewage treatment plants under the construction grants program. Congress overrode a presidential veto to pass the law, and the stated aim was to make waters \"fishable and swimmable.\" Assessments of its results differ. The EPA credits the law with making waters safer and cleaner, while critics argue that the broad scope of powers that the EPA claims makes it possible for property owners to break the law without meaning to.\n\nForests, rangelands, and wildfire\n\nFederal land is administered for several purposes at once. Federal land is managed for many purposes, such as the conservation and development of natural resources, grazing and recreation. The Forest Service and the Bureau of Land Management operate under similar multiple-use, sustained-yield mandates, which produces friction between logging, grazing, mining, and recreation on one side and conservation on the other. The concentration of federal land in the West has contributed to a higher degree of controversy over federal land ownership and use in that part of the country. In 2025, a Senate committee proposal tied to a federal budget bill would have required the sale of between 2.2 million and 3.3 million acres of public land across 11 Western states, including Alaska. The proposal exempted national parks and monuments. Wildfire management, forest thinning, and rangeland restoration are contested as well, with debates over suppression, prescribed burning, and the balance between fuel reduction and habitat protection.\n\nEnergy production and emissions\n\nEnergy extraction on federal land, including oil, natural gas, and coal leasing, is a significant source of conflict and revenue. Environmental review of major federal projects is governed largely by the National Environmental Policy Act of 1970. National climate and emissions policy has shifted substantially between presidential administrations, moving between regulatory measures for power plants and vehicles, incentives for renewable-energy, and reliance on market and state-level action. The environmental effects of petroleum, natural-gas, and coal production, including air pollution, methane releases, and habitat disturbance, remain central to these debates. Federal policy on greenhouse-gas emissions and on climate-change adaptation, such as flood management and wildfire preparedness, continues to be contested between federal and state authorities."
    },
    {
      "heading": "Contested Questions and Open Challenges",
      "text": "Water scarcity in the arid West is the most immediate of these challenges. The Colorado River irrigates more than 5 million acres of farmland and supplies roughly 40 million people in seven states and Mexico, and its two main reservoirs, Lake Powell and Lake Mead, have fallen to historic lows. On July 12, 2026, Lake Powell stood at about 3,524 feet and Lake Mead just below 1,043 feet, both below the records set in 2023. Glen Canyon Dam, completed in 1963, was not designed to operate at such low levels. In late July 2026 the Bureau of Reclamation issued a framework that runs through 2036 and uses operational \"guardrails\" in two-year plans. Under it, Arizona, California and Nevada must cut their use of Colorado River water by roughly 20 percent over two years, while Colorado, Utah, New Mexico and Wyoming are not subject to mandatory cuts for now. Published estimates of the maximum permitted Lower Basin shortage differ, with some sources citing 3.0 million acre-feet a year and others 3.6 million. The core dispute is how to divide shortages among cities, irrigated agriculture, hydropower and ecosystems. Reduced reservoir levels also lower hydropower output at Hoover Dam, and cold-water releases from Glen Canyon Dam have been linked to reduced spawning of warm-water fish downstream. Similar pressures apply to aquifers and irrigated regions across the Great Plains and the West, where groundwater withdrawals often exceed recharge.\n\nIncome disparities are a second persistent issue, and they operate at several scales. In the Census Bureau's 2024 American Community Survey, the District of Columbia had the highest median household income of any jurisdiction, while Maryland, Massachusetts and New Jersey led among states. Arkansas, Louisiana, Mississippi and West Virginia recorded the lowest figures. Gaps within states are often as sharp as those between them, with high-cost metropolitan cores and lower-income rural counties sitting side by side. National inequality measures moved little in the most recent data. The Census Bureau's 2025 income report found that median household income after taxes and transfers rose about 3.1 percent to roughly $76,000, and that the Gini index did not change significantly from 2024. Gains were also uneven across demographic groups: median income rose for Black households in 2025 but did not change significantly for Asian or Hispanic households. The persistence of disparities across income distribution therefore reflects differences in regional labor markets, education, housing costs and the distribution of public transfers.\n\nClimate change intensifies several of these pressures at once. Snowpack is the main source of Colorado River flow, and in spring 2026 snowpack in the Rocky Mountains fell to a record low share of normal, which accounts for much of the reservoir decline. Along the coasts, rising sea levels increase flooding and erosion risk for cities and wetlands on the Atlantic and Gulf coasts. Extreme heat is more dangerous in dense cities, where the urban-heat-island effect compounds warming. In the West, longer fire seasons and changing climate patterns affect forests, rangelands and communities at the wildland–urban boundary. Shifts in storm frequency and intensity along both coasts raise questions about infrastructure design, insurance costs and the adequacy of existing infrastructure.\n\nDebates over the balance of federal and state authority and the status of Indigenous nations remain unsettled. Under the federal system, states and the national government share control over water allocation, and interstate compacts govern the Colorado River, which makes agreement on shortages difficult. Federal courts have also repeatedly redrawn the boundaries of jurisdiction. In 2020 the Supreme Court held, in a 5–4 decision, that a reservation in eastern Oklahoma had never been disestablished, which expanded tribal criminal jurisdiction over a large area. In 2022 a 5–4 majority in Oklahoma v. Castro-Huerta allowed state prosecution of non-Native people who commit crimes against Native people on reservations, a ruling that tribal advocates and some legal scholars have criticized as departing from long-standing federal Indian law. The federal government's relationship with tribes is commonly described as a trust relationship, though its legal limits are not clearly defined. Current disputes include rising violent crime on some reservations, litigation over land and water rights, and conflicts over tribal gaming and border construction. These issues are framed differently by tribal governments, states and federal agencies, and their resolution depends on Congress, the courts and negotiated agreements."
    }
  ],
  "links": [
    "canada",
    "mexico",
    "gross-domestic-product",
    "mountain",
    "glacier",
    "climate",
    "ecosystem",
    "plate-tectonics",
    "river",
    "aquifer",
    "archaeology",
    "federalism",
    "constitution",
    "united-states-constitution",
    "drainage-basin",
    "eutrophication",
    "sovereignty",
    "labor-market",
    "separation-of-powers",
    "judicial-review",
    "cloud-computing",
    "federal-reserve-system",
    "exchange-rate",
    "world-trade-organization",
    "internet",
    "world-wide-web",
    "semiconductor",
    "silicon-valley",
    "high-speed-rail",
    "insurance",
    "united-nations",
    "united-nations-security-council",
    "world-bank",
    "international-criminal-court",
    "international-court-of-justice",
    "international-law",
    "renewable-energy",
    "petroleum",
    "natural-gas",
    "coal",
    "greenhouse-gas",
    "climate-change",
    "groundwater",
    "income-inequality",
    "sea-level-rise",
    "infrastructure"
  ],
  "sources": [
    {
      "title": "Geography of the United States",
      "url": "https://en.wikipedia.org/wiki/Geography_of_the_United_States"
    },
    {
      "title": "Photos of United States",
      "url": "https://www.cia.gov/the-world-factbook/about/archives/2023/countries/united-states"
    },
    {
      "title": "CIA -- The World Factbook -- United States - DAML.org",
      "url": "https://www.daml.org/2001/12/factbook/us.html"
    },
    {
      "title": "United States",
      "url": "https://relief.unboundmedicine.com/relief/view/The-World-Factbook/563237/all/United_States"
    },
    {
      "title": "Area — United States - CIA World Factbook Archive",
      "url": "https://worldfactbookarchive.org/archive/field/US/Area"
    },
    {
      "title": "Territories of the United States",
      "url": "https://en.wikipedia.org/wiki/Territories_of_the_United_States"
    },
    {
      "title": "U.S. territorial sovereignty",
      "url": "https://en.wikipedia.org/wiki/U.S._territorial_sovereignty"
    },
    {
      "title": "List of states and territories of the United States",
      "url": "https://en.wikipedia.org/wiki/List_of_states_and_territories_of_the_United_States"
    },
    {
      "title": "Insular area",
      "url": "https://en.wikipedia.org/wiki/Insular_area"
    },
    {
      "title": "Insular areas of the United States - Wikimedia Commons",
      "url": "https://commons.wikimedia.org/wiki/Insular_areas_of_the_United_States"
    },
    {
      "title": "What are the US Territories?",
      "url": "https://study.com/academy/lesson/territories-of-the-united-states.html"
    },
    {
      "title": "US Territories Map - All 5 Inhabited Territories + DC",
      "url": "https://mapunitedstates.com/territories/"
    },
    {
      "title": "On this day, the name “United States of America” becomes official",
      "url": "https://constitutioncenter.org/blog/today-the-name-united-states-of-america-becomes-offici"
    },
    {
      "title": "Sandboxx News",
      "url": "https://www.sandboxx.us/news/why-were-we-named-america/"
    },
    {
      "title": "United Colonies",
      "url": "https://en.wikipedia.org/wiki/United_Colonies"
    },
    {
      "title": "Congress renames the nation “United States of America”",
      "url": "https://www.history.com/this-day-in-history/september-9/congress-renames-the-nation-united-states-of-america"
    },
    {
      "title": "United States Declaration of Independence",
      "url": "https://en.wikipedia.org/wiki/United_States_Declaration_of_Independence"
    },
    {
      "title": "Constitution of the United States",
      "url": "https://en.wikipedia.org/wiki/Constitution_of_the_United_States"
    },
    {
      "title": "Declaration of Independence",
      "url": "https://www.statutesandstories.com/blog_html/declaration-of-independence/"
    },
    {
      "title": "Geographic Terms and Definitions",
      "url": "https://www.census.gov/programs-surveys/popest/about/glossary/geo-terms.html"
    },
    {
      "title": "Regions of the United States: the 4 Regions and 50 States",
      "url": "https://americain.org/en/understanding-the-us/geography-regions"
    },
    {
      "title": "Regions of the United States: Census Regions, 5-Region Model and 7-Region Framework - The Facts Institute",
      "url": "https://factsinstitute.com/countries/regions-of-the-united-states/"
    },
    {
      "title": "U.S. Regions History & Importance - Lesson",
      "url": "https://study.com/academy/lesson/what-are-the-regions-of-the-united-states.html"
    },
    {
      "title": "US Regions and Divisions Explained - Northeast, Midwest, South, West",
      "url": "https://mapunitedstates.com/regions/"
    },
    {
      "title": "American cultural regions mapped through the lexical analysis of social media",
      "url": "https://arxiv.org/pdf/2208.07649"
    },
    {
      "title": "Northwestern United States",
      "url": "https://en.wikipedia.org/wiki/Northwestern_United_States"
    },
    {
      "title": "Which States Border Alaska?",
      "url": "https://www.worldatlas.com/articles/which-states-border-alaska.html"
    },
    {
      "title": "What Are The Contiguous United States?",
      "url": "https://www.worldatlas.com/articles/what-are-the-contiguous-united-states.html"
    },
    {
      "title": "Glossary - U.S. Energy Information Administration (EIA)",
      "url": "https://www.eia.gov/tools/glossary/index.php?id=Census+Region"
    },
    {
      "title": "Contiguous United States",
      "url": "https://en.wikipedia.org/wiki/Contiguous_United_States"
    },
    {
      "title": "Geography of Alaska",
      "url": "https://en.wikipedia.org/wiki/Geography_of_Alaska"
    },
    {
      "title": "Non Contiguous US States: What You Need To Know About Alaska And Hawaii - Wishart Lab",
      "url": "https://ccdb3.wishartlab.com/ccd/non-contiguous-us-states-what-you-need-to-know-about-alaska-and-hawaii"
    },
    {
      "title": "An Outline of American Geography - Chapter 2",
      "url": "https://usinfo.org/enus/life/geotravel/geograph/geog02.htm"
    },
    {
      "title": "The 8 geographical regions of North America Flashcards",
      "url": "https://quizlet.com/94592572/the-8-geographical-regions-of-north-america-flash-cards/"
    },
    {
      "title": "Interior Lowlands",
      "url": "https://www.britannica.com/place/Interior-Lowlands-region-North-America"
    },
    {
      "title": "16.2: Physiograhic Provinces of the United States of America - Geosciences LibreTexts",
      "url": "https://geo.libretexts.org/Courses/Lumen_Learning/Physical_Geology_(Lumen)/16:_Geologic_History_of_North_America/16.02:_Physiograhic_Provinces_of_the_United_States_of_America"
    },
    {
      "title": "The Interior Lowlands - Article",
      "url": "https://mrnussbaum.com/the-interior-lowlands-article"
    },
    {
      "title": "Alaska Range",
      "url": "https://en.wikipedia.org/wiki/Alaska_Range"
    },
    {
      "title": "Amak Volcano",
      "url": "https://en.wikipedia.org/wiki/Amak_Volcano"
    },
    {
      "title": "Mount Vsevidof",
      "url": "https://en.wikipedia.org/wiki/Mount_Vsevidof"
    },
    {
      "title": "Mauna Kea",
      "url": "https://www.worldatlas.com/volcanoes/mauna-kea.html"
    },
    {
      "title": "Mauna Kea",
      "url": "https://en.wikipedia.org/wiki/Mauna_Kea"
    },
    {
      "title": "The Lowest Point in Every U.S. State - Geography Realm",
      "url": "https://www.geographyrealm.com/the-lowest-point-in-every-u-s-state/"
    },
    {
      "title": "United States: lowest point in each state",
      "url": "https://www.statista.com/statistics/1325443/lowest-points-united-states-state/"
    },
    {
      "title": "Inyo County, California",
      "url": "https://en.wikipedia.org/wiki/Inyo_County,_California"
    },
    {
      "title": "List of physiographic regions",
      "url": "https://en.wikipedia.org/wiki/List_of_physiographic_regions"
    },
    {
      "title": "Physiographic regions of the United States",
      "url": "https://en.wikipedia.org/wiki/Physiographic_regions_of_the_United_States"
    },
    {
      "title": "The Eight Physiographic Regions Of The United States",
      "url": "https://www.worldatlas.com/articles/the-eight-physiographic-regions-of-the-united-states.html"
    },
    {
      "title": "Eight Geographic Regions of North America Flashcards",
      "url": "https://quizlet.com/223293860/eight-geographic-regions-of-north-america-flash-cards/"
    },
    {
      "title": "U.S. States With the Most Extreme Elevation Spans - Geography Realm",
      "url": "https://www.geographyrealm.com/states-elevation-span/"
    },
    {
      "title": "List of elevation extremes by region",
      "url": "https://en.wikipedia.org/wiki/List_of_elevation_extremes_by_region"
    },
    {
      "title": "The Tallest Mountain In America From Base To Summit",
      "url": "https://www.worldatlas.com/mountains/the-tallest-mountain-in-america-from-base-to-summit.html"
    },
    {
      "title": "Canadian Shield",
      "url": "https://en.wikipedia.org/wiki/Canadian_Shield"
    },
    {
      "title": "Laurentia",
      "url": "https://en.wikipedia.org/wiki/Laurentia"
    },
    {
      "title": "Laramide orogeny",
      "url": "https://en.wikipedia.org/wiki/Laramide_orogeny"
    },
    {
      "title": "The Laramide orogeny: Current understanding of the structural style, timing, and spatial distribution of the classic foreland thick-skinned tectonic system",
      "url": "https://pubs.geoscienceworld.org/gsa/books/edited-volume/2357/chapter/135072889/The-Laramide-orogeny-Current-understanding-of-the"
    },
    {
      "title": "Plate Tectonics - Pacific Northwest Seismic Network",
      "url": "https://pnsn.org/education/seismology/plate-tectonics"
    },
    {
      "title": "Cascadia subduction zone",
      "url": "https://en.wikipedia.org/wiki/Cascadia_subduction_zone"
    },
    {
      "title": "The San Andreas and Cascadia Earthquake Faults May Be Linked",
      "url": "https://www.scientificamerican.com/article/the-san-andreas-and-cascadia-earthquake-faults-may-be-linked/"
    },
    {
      "title": "Juan De Fuca Plate - an overview",
      "url": "https://www.sciencedirect.com/topics/earth-and-planetary-sciences/juan-de-fuca-plate"
    },
    {
      "title": "Mississippi River",
      "url": "https://en.wikipedia.org/wiki/Mississippi_River"
    },
    {
      "title": "Missouri River",
      "url": "https://en.wikipedia.org/wiki/Missouri_River"
    },
    {
      "title": "Mississippi River System",
      "url": "https://en.wikipedia.org/wiki/Mississippi_River_System"
    },
    {
      "title": "Mississippi (river Us)",
      "url": "https://www.encyclopedia.com/places/united-states-and-canada/us-physical-geography/mississippi-river-us"
    },
    {
      "title": "New Orleans District > Missions > Mississippi River Flood Control > Mississippi River & Tributaries > Mississippi Drainage Basin",
      "url": "https://www.mvn.usace.army.mil/Missions/Mississippi-River-Flood-Control/Mississippi-River-Tributaries/Mississippi-Drainage-Basin/"
    },
    {
      "title": "New Orleans District > About > Projects > Mississippi River > Mississippi Drainage Basin",
      "url": "https://www.mvn.usace.army.mil/About/Projects/Mississippi-River/Mississippi-Drainage-Basin/"
    },
    {
      "title": "Missouri River",
      "url": "https://riversinsight.com/missouri-river/"
    },
    {
      "title": "Water Action Hub",
      "url": "https://wateractionhub.org/basin-collaborative/mississippi-river/sub-basins/missouri-river-basin/"
    },
    {
      "title": "Great Lakes Water Withdrawals: Legal and Policy Issues",
      "url": "https://www.congress.gov/crs-product/RL32956"
    },
    {
      "title": "Great Lakes Compact - Water",
      "url": "https://www.in.gov/dnr/water/lake-michigan/great-lakes-compact/"
    },
    {
      "title": "Great Lakes Compact and diversions",
      "url": "https://dnr.wisconsin.gov/topic/WaterUse/Compact.html"
    },
    {
      "title": "Great Lakes Compact",
      "url": "https://ohiodnr.gov/discover-and-learn/safety-conservation/about-ODNR/water-resources/water-inventory-planning/great-lakes-compact"
    },
    {
      "title": "Protecting the Great Lakes",
      "url": "https://www.nwf.org/Our-Work/Waters/Great-Waters-Restoration/Great-Lakes"
    },
    {
      "title": "Great Lakes fast facts",
      "url": "https://www.michiganseagrant.org/topics/great-lakes-fast-facts/"
    },
    {
      "title": "The US and Canada have long managed the Great Lakes together. That era could be ending.",
      "url": "https://grist.org/politics/us-canada-great-lakes-water-sharing-political-tensions/"
    },
    {
      "title": "US-Canada Great Lakes water-sharing at risk amid political tensions",
      "url": "https://planetdetroit.org/2025/03/us-canada-great-lakes-water-sharing/"
    },
    {
      "title": "Colorado River Developments and Potential Compact Litigation",
      "url": "https://ktslaw.com/en/insights/alert/2026/4/colorado%20river%20developments%20and%20potential%20compact%20litigation"
    },
    {
      "title": "Colorado River Water Crisis: What You Need to Know",
      "url": "https://www.circleofblue.org/the-colorado-river/"
    },
    {
      "title": "Everything you need to know about the new federal report on the Colorado River's future",
      "url": "https://coloradosun.com/2026/07/31/colorado-river-breakdown-management-plan-federal-report/"
    },
    {
      "title": "The Colorado River States are Deadlocked and the River is Crashing. Will a ‘Grand Bargain’ Finally Get its Day? - Water Education Foundation",
      "url": "https://www.watereducation.org/western-water/colorado-river-states-are-deadlocked-and-river-crashing-will-grand-bargain-finally-get"
    },
    {
      "title": "Colorado River System During Historic Drought",
      "url": "https://www.usbr.gov/newsroom/news-release/5326"
    },
    {
      "title": "Colorado River managers warn of worsening conditions, looming cuts and shrinking reservoirs - The Gazette",
      "url": "https://gazette.com/2026/09/15/colorado-river-managers-warn-of-worsening-conditions-looming-cuts-and-shrinking-reservoirs/"
    },
    {
      "title": "What Are The Climate Zones Of The US?",
      "url": "https://www.worldatlas.com/articles/what-are-the-climate-zones-of-the-usa.html"
    },
    {
      "title": "10.3 Köppen Classification System",
      "url": "https://slcc.pressbooks.pub/physicalgeography/chapter/10-3/"
    },
    {
      "title": "United States Koppen-Geiger Climate Classification Map",
      "url": "https://www.plantmaps.com/koppen-climate-classification-map-united-states.php"
    },
    {
      "title": "Climate of the United States",
      "url": "https://en.wikipedia.org/wiki/Climate_of_the_United_States"
    },
    {
      "title": "Dividing line: The past, present and future of the 100th Meridian",
      "url": "https://www.earthmagazine.org/article/dividing-line-past-present-and-future-100th-meridian/"
    },
    {
      "title": "Whither the 100th Meridian? The once and future physical and human geography of America’s arid-humid divide: Part I: The story so far",
      "url": "https://escholarship.org/uc/item/7sm3k7h4"
    },
    {
      "title": "Whither the 100th Meridian? The Once and Future Physical and Human Geography of America’s Arid–Humid Divide. Part I: The Story So Far in: Earth Interactions Volume 22 Issue 5 (2018)",
      "url": "https://journals.ametsoc.org/view/journals/eint/22/5/ei-d-17-0011.1.xml"
    },
    {
      "title": "Average Annual Temperatures by USA State - Current Results",
      "url": "https://www.currentresults.com/Weather/US/average-annual-state-temperatures.php"
    },
    {
      "title": "Average Annual Precipitation by USA State - Current Results",
      "url": "https://www.currentresults.com/Weather/US/average-annual-state-precipitation.php"
    },
    {
      "title": "United States rainfall climatology",
      "url": "https://en.wikipedia.org/wiki/United_States_rainfall_climatology"
    },
    {
      "title": "Average Temperature by City & State (NOAA)",
      "url": "https://plainclimate.com/"
    },
    {
      "title": "Assessing the U.S. Temperature and Precipitation Analysis in 2025",
      "url": "https://www.ncei.noaa.gov/news/national-climate-202513"
    },
    {
      "title": "Signs of Winter 8: The 100th Meridian (Part 2)!",
      "url": "https://sites.psu.edu/ecologistsnotebook/2021/01/21/signs-of-winter-8-the-100th-meridian-part-2/"
    },
    {
      "title": "Biome Map Coloring (pdf) - CliffsNotes",
      "url": "https://www.cliffsnotes.com/study-notes/23387865"
    },
    {
      "title": "Terrestrial Biomes",
      "url": "https://open.lib.umn.edu/environmentalbiology/chapter/terrestrial-biomes/"
    },
    {
      "title": "Hawaiian tropical high shrublands",
      "url": "https://en.wikipedia.org/wiki/Hawaiian_tropical_high_shrublands"
    },
    {
      "title": "90% of Hawaii's Native Species Are Endemic, But Only on Land",
      "url": "https://www.lovebigisland.com/quick-and-remarkable-facts-about-hawaii/endemic-species-hawaii/"
    },
    {
      "title": "Islands host 1/3 of Earth’s plant species, conservation needed",
      "url": "https://www.hawaii.edu/news/2024/10/16/islands-host-one-third-earths-plants/"
    },
    {
      "title": "Population Genetics of the Endemic Hawaiian Species Chrysodracon hawaiiensis and Chrysodracon auwahiensis (Asparagaceae): Insights from RAPD and ISSR Variation",
      "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5000738/"
    },
    {
      "title": "Western short grasslands",
      "url": "https://en.wikipedia.org/wiki/Western_short_grasslands"
    },
    {
      "title": "What is an invasive species and why are they a problem?",
      "url": "https://www.usgs.gov/faqs/what-invasive-species-and-why-are-they-a-problem"
    },
    {
      "title": "The Cost of Invasive Species U.S. Fish & Wildlife Service",
      "url": "https://www.perc.org/wp-content/uploads/2016/09/costofinvasivesfactsheet.pdf"
    },
    {
      "title": "Invasive Species",
      "url": "https://www.nwf.org/Educational-Resources/Wildlife-Guide/Threats-to-Wildlife/Invasive-Species"
    },
    {
      "title": "Biomes",
      "url": "https://courses.lumenlearning.com/ivytech-wmopen-nmbiology/chapter/biomes/"
    },
    {
      "title": "Hawaii Conservation Summary // LandScope America",
      "url": "http://www.landscope.org/hawaii/overview/"
    },
    {
      "title": "Cahokia Mounds State Historic Site - UNESCO World Heritage Centre",
      "url": "https://whc.unesco.org/en/list/198/"
    },
    {
      "title": "Cahokia Mounds",
      "url": "https://www.britannica.com/place/Cahokia-Mounds"
    },
    {
      "title": "American Bottom",
      "url": "https://en.wikipedia.org/wiki/American_Bottom"
    },
    {
      "title": "Ancestral Puebloans of the Four Corners Region",
      "url": "https://coloradoencyclopedia.org/article/ancestral-puebloans-four-corners-region"
    },
    {
      "title": "Great house (pueblo)",
      "url": "https://en.wikipedia.org/wiki/Great_house_(pueblo)"
    },
    {
      "title": "Ancestral Puebloan - Science of the American Southwest (U.S. National Park Service)",
      "url": "https://www.nps.gov/subjects/swscience/ancestral-puebloan.htm"
    },
    {
      "title": "The Federal Recognition of Tribes: Frequently Asked Questions",
      "url": "https://www.congress.gov/crs-product/R48888"
    },
    {
      "title": "The 574 Federally Recognized Indian Tribes in the United States",
      "url": "https://www.congress.gov/crs-product/R47414"
    },
    {
      "title": "Cahokia",
      "url": "https://en.wikipedia.org/wiki/Cahokia"
    },
    {
      "title": "Ancestral Puebloan dwellings",
      "url": "https://en.wikipedia.org/wiki/Ancestral_Puebloan_dwellings"
    },
    {
      "title": "The U.S.: Acquisitions of Territory, 1783-1853 - Map Quiz Game - Seterra",
      "url": "https://www.geoguessr.com/vgp/3362"
    },
    {
      "title": "Gadsden Purchase",
      "url": "https://www.britannica.com/event/Gadsden-Purchase"
    },
    {
      "title": "Gadsden Purchase Completes the U.S.-Mexican Border",
      "url": "https://www.ebsco.com/research-starters/history/gadsden-purchase-completes-us-mexican-border/"
    },
    {
      "title": "United States territorial acquisitions table",
      "url": "https://en.wikipedia.org/wiki/United_States_territorial_acquisitions_table"
    },
    {
      "title": "Gadsden Purchase - Kids",
      "url": "https://kids.britannica.com/kids/article/Gadsden-Purchase/399473"
    },
    {
      "title": "U.S. Senate ratifies purchase of Alaska from Russia on April 9, 1867. - HistoryLink.org",
      "url": "https://www.historylink.org/File/5406"
    },
    {
      "title": "Introduction - Alaska Purchase Treaty: Primary Documents in American History - Research Guides at Library of Congress",
      "url": "https://guides.loc.gov/alaska-treaty"
    },
    {
      "title": "U.S. takes possession of Alaska",
      "url": "https://www.history.com/this-day-in-history/october-18/u-s-takes-possession-of-alaska"
    },
    {
      "title": "Seward’s Folly",
      "url": "https://www.loc.gov/item/today-in-history/march-30/"
    },
    {
      "title": "Newlands Resolution",
      "url": "https://en.wikipedia.org/wiki/Newlands_Resolution"
    },
    {
      "title": "Annexation of Hawaii",
      "url": "https://study.com/learn/lesson/sanford-b-dole-the-annexation-of-hawaii.html"
    },
    {
      "title": "History of U.S. foreign policy, 1897%E2%80%931913",
      "url": "https://en.wikipedia.org/wiki/History_of_U.S._foreign_policy,_1897%E2%80%931913"
    },
    {
      "title": "Annexation of Hawaii — APUSH Definition & Exam Guide",
      "url": "https://fiveable.me/apush/key-terms/annexation-of-hawaii"
    },
    {
      "title": "Treaty of Paris",
      "url": "https://omniatlas.com/maps/asia-pacific/18981210/"
    },
    {
      "title": "Primary Sources from U.S. Overseas Expansion - Overview of the Overseas Expansion Debate",
      "url": "https://education.cfr.org/learn/learning-journey/primary-sources-us-overseas-expansion/overview-of-the-overseas-expansion-debate"
    },
    {
      "title": "Annexation of Hawaii, 1898 - state.gov",
      "url": "https://2001-2009.state.gov/r/pa/ho/time/gp/17661.htm"
    },
    {
      "title": "Demographics of the United States",
      "url": "https://en.wikipedia.org/wiki/Demographics_of_the_United_States"
    },
    {
      "title": "Four takeaways from the new Census population estimates",
      "url": "https://jedkolko.substack.com/p/four-takeaways-from-the-new-census"
    },
    {
      "title": "Urban and Rural Population (2020) - Rural - SparkMap",
      "url": "https://sparkmap.org/data-info/urban-and-rural-population-2020-rural/"
    },
    {
      "title": "Federal Register :: 2020 Census Qualifying Urban Areas and Final Criteria Clarifications",
      "url": "https://www.federalregister.gov/documents/2022/12/29/2022-28286/2020-census-qualifying-urban-areas-and-final-criteria-clarifications"
    },
    {
      "title": "Rural Classifications - What is Rural?",
      "url": "https://www.ers.usda.gov/topics/rural-economy-population/rural-classifications/what-is-rural"
    },
    {
      "title": "United States Demographics 2026: Population Growth, Migration, Age Structure and Fertility",
      "url": "https://demographer.org/countries/united-states-demographics/"
    },
    {
      "title": "Populations in All Age Groups Growing in the South, Driven by Outlying Counties in Metro Areas",
      "url": "https://www.census.gov/newsroom/press-releases/2026/vintage-2025-pop-estimates.html"
    },
    {
      "title": "U.S. Population Growth Slows Due to Historic Decline in Net International Migration",
      "url": "https://www.census.gov/newsroom/press-releases/2026/population-growth-slows.html"
    },
    {
      "title": "Women Still Outnumbered Men Among the Oldest, but Gap is Narrowing",
      "url": "https://www.census.gov/library/stories/2026/04/age-and-sex.html"
    },
    {
      "title": "The Demographic Outlook: 2025 to 2055",
      "url": "https://www.cbo.gov/publication/61164"
    },
    {
      "title": "An Update to the Demographic Outlook, 2025 to 2055",
      "url": "https://www.cbo.gov/publication/61390"
    },
    {
      "title": "United States Bill of Rights",
      "url": "https://en.wikipedia.org/wiki/United_States_Bill_of_Rights"
    },
    {
      "title": "Bill of Rights U.S. Constitution - FindLaw",
      "url": "https://constitution.findlaw.com/bill-of-rights.html"
    },
    {
      "title": "New Blog Series: “Constitutional Amendments – Creating A More Perfect Union”",
      "url": "https://reagan.blogs.archives.gov/2022/07/25/new-blog-series-constitutional-amendments-creating-a-more-perfect-union"
    },
    {
      "title": "Marbury v. Madison and Judicial Review",
      "url": "https://www.law.cornell.edu/constitution-conan/article-3/section-1/marbury-v-madison-and-judicial-review"
    },
    {
      "title": "Marbury v. Madison",
      "url": "https://www.fjc.gov/history/cases/cases-that-shaped-the-federal-courts/marbury-v-madison"
    },
    {
      "title": "How Marbury v. Madison Created Judicial Review",
      "url": "https://govfacts.org/government/federal/federal-court-system/judicial-review/how-marbury-v-madison-created-judicial-review/"
    },
    {
      "title": "The Bill of Rights: A Transcription",
      "url": "https://www.archives.gov/founding-docs/bill-of-rights-transcript"
    },
    {
      "title": "• Constitution Day: The Full U.S. Constitution Virtual Exhibit",
      "url": "https://visit.archives.gov/whats-on/explore-exhibits/constitution-day-full-us-constitution-virtual-exhibit"
    },
    {
      "title": "United States GDP 2025 - StatisticsTimes.com",
      "url": "https://statisticstimes.com/economy/country/usa-gdp.php"
    },
    {
      "title": "US GDP by Sector 2025 — Services 82.8%, Industry 16.4%",
      "url": "https://ecoindica.com/us-gdp/"
    },
    {
      "title": "What is the gross domestic product (GDP) in the US?",
      "url": "https://usafacts.org/answers/what-is-the-gross-domestic-product-gdp/country/united-states/"
    },
    {
      "title": "Agriculture in the United States",
      "url": "https://en.wikipedia.org/wiki/Agriculture_in_the_United_States"
    },
    {
      "title": "Corn and Other Feed Grains - Feed Grains Sector at a Glance",
      "url": "https://www.ers.usda.gov/topics/crops/corn-and-other-feed-grains/feed-grains-sector-at-a-glance"
    },
    {
      "title": "Wheat Exports: The Balancing Act of U.S. Wheat",
      "url": "https://www.fb.org/intel/markets/wheat-exports-the-balancing-act-of-u-s-wheat"
    },
    {
      "title": "From Fields to Overseas Markets: Mapping U.S. State Agricultural Exports",
      "url": "https://www.fas.usda.gov/data/mapping-us-state-agricultural-exports"
    },
    {
      "title": "The United States set record energy production in 2025, again - U.S. Energy Information Administration (EIA)",
      "url": "https://www.eia.gov/todayinenergy/detail.php?id=67684"
    },
    {
      "title": "U.S. energy facts explained - consumption and production - U.S. Energy Information Administration (EIA)",
      "url": "https://www.eia.gov/energyexplained/us-energy-facts/"
    },
    {
      "title": "Electricity in the U.S. - U.S. Energy Information Administration (EIA)",
      "url": "https://www.eia.gov/energyexplained/electricity/electricity-in-the-us.php"
    },
    {
      "title": "US Sets Record for Energy Production in 2025",
      "url": "https://jpt.spe.org/us-sets-record-for-energy-production-in-2025"
    },
    {
      "title": "US Energy Production — Oil, Gas, Coal, Nuclear & Renewables Data",
      "url": "https://usfiscalclock.com/energy-output"
    },
    {
      "title": "U.S. Energy Facts 2025: Production, Consumption, Prices & Energy Mix",
      "url": "https://energyfactbook.com/us-energy-facts/"
    },
    {
      "title": "US Language Statistics 2026",
      "url": "https://www.theglobalstatistics.com/us-language-statistics/"
    },
    {
      "title": "Most Spoken Languages in the US (2026 Data Guide)",
      "url": "https://www.vmeg.ai/blog/most-spoken-languages-in-the-us/"
    },
    {
      "title": "Language Access Statistics in the U.S. (2026)",
      "url": "https://accessmultilingual.com/resources/language-access-statistics-united-states-2026"
    },
    {
      "title": "languages we speak in united states",
      "url": "https://census.gov/library/stories/2022/12/languages-we-speak-in-united-states.html"
    },
    {
      "title": "At Least 350 Languages Spoken In U.S. Homes: New Report",
      "url": "https://www.nbcnews.com/news/latino/guess-how-many-languages-are-spoken-u-s-homes-n456656"
    },
    {
      "title": "language at home acs 5 year",
      "url": "https://census.gov/newsroom/press-releases/2023/language-at-home-acs-5-year.html"
    },
    {
      "title": "US Christian Decline May Be Stabilizing: 2023-24 Religious Landscape Study (RLS)",
      "url": "https://www.pewresearch.org/religion/2025/02/26/decline-of-christianity-in-the-us-has-slowed-may-have-leveled-off/"
    },
    {
      "title": "Religious landscape: The US Christian population has declined for years. A new survey shows that drop levelling off - Sight Magazine",
      "url": "https://sightmagazine.com.au/features/religious-landscape-the-us-christian-population-has-declined-for-years-a-new-survey-shows-that-drop-levelling-off/"
    },
    {
      "title": "6 in 10 US adults say they’re Christians",
      "url": "https://baptistnews.com/article/6-in-10-us-adults-say-theyre-christians/"
    },
    {
      "title": "Overview of the Religion Clauses (Establishment and Free Exercise Clauses)",
      "url": "https://www.law.cornell.edu/constitution-conan/amendment-1/overview-of-the-religion-clauses-establishment-and-free-exercise-clauses"
    },
    {
      "title": "Relationship Between the Establishment and Free Exercise Clauses",
      "url": "https://constitution.congress.gov/browse/essay/amdt1-5/ALDE_00000039/"
    },
    {
      "title": "The Free Exercise Clause: What You Need to Know",
      "url": "https://www.freedomforum.org/free-exercise-clause/"
    },
    {
      "title": "Free Exercise of Religion/Establishment Clause - Historical Society of the New York Courts",
      "url": "https://history.nycourts.gov/democracy-teacher-toolkit/first-amendment-civil-liberties/free-religion/"
    },
    {
      "title": "American Community Survey Reports Language Use in the United States: 2019",
      "url": "https://www.census.gov/content/dam/Census/library/publications/2022/acs/acs-50.pdf"
    },
    {
      "title": "How Many Languages Are Actually Spoken in the United States? - Elmura Linguistics",
      "url": "https://elmuralinguistics.com/how-many-languages-are-spoken-in-united-states/"
    },
    {
      "title": "Nearly 38 Million In U.S. Speak Spanish At Home, Census Says",
      "url": "https://www.foxnews.com/politics/nearly-38-million-in-u-s-speak-spanish-at-home-census-says.amp"
    },
    {
      "title": "Decline of Christianity in the U.S. Has Slowed, May Have ...",
      "url": "https://www.pewresearch.org/wp-content/uploads/sites/20/2025/02/PR_2025.02.26_religious-landscape-study_report.pdf"
    },
    {
      "title": "The US Christian population has declined for years. A new survey shows that drop leveling off",
      "url": "https://www.yahoo.com/news/us-christian-population-declined-years-125504099.html"
    },
    {
      "title": "The First Amendment’s Free Exercise Clause - FindLaw",
      "url": "https://constitution.findlaw.com/amendment1/annotation16.html"
    },
    {
      "title": "US Education System (2026): Structure, Quality, and Performance",
      "url": "https://educationbycountry.org/country/us/"
    },
    {
      "title": "The US Education System: Structure, Levels, How It Works",
      "url": "https://ieltsidpindia.com/blog/the-us-education-system"
    },
    {
      "title": "Education System in the USA: Levels & Grading 2025–26",
      "url": "https://leapscholar.com/blog/education-system-in-the-usa-understanding-the-schooling-system-in-the-usa/"
    },
    {
      "title": "The Education System in the US Explained - TutorChase",
      "url": "https://www.tutorchase.com/blog/the-education-system-in-united-states-explained"
    },
    {
      "title": "U.S. R&D Totaled $937 Billion in 2023; Estimate for 2024 Indicates Further Increase to $993 Billion",
      "url": "https://ncses.nsf.gov/pubs/nsf26314"
    },
    {
      "title": "Ranked: The Countries Investing the Most in R&D",
      "url": "https://www.visualcapitalist.com/rd-investment-by-country/"
    },
    {
      "title": "Long-Term Trends Show Decline in Federally Funded R&D as a Share of GDP while Business-Funded R&D Share Increases",
      "url": "https://ncses.nsf.gov/pubs/nsf25334"
    },
    {
      "title": "Experimental R&D Value Added Statistics for the U.S. and States Now Available",
      "url": "https://www.bea.gov/news/blog/2024-05-09/experimental-rd-value-added-statistics-us-and-states-now-available"
    },
    {
      "title": "List of Nobel laureates by country",
      "url": "https://en.wikipedia.org/wiki/List_of_Nobel_laureates_by_country"
    },
    {
      "title": "Nobel Prize Winners By Country",
      "url": "https://www.worldatlas.com/articles/top-30-countries-with-nobel-prize-winners.html"
    },
    {
      "title": "List of American Nobel laureates",
      "url": "https://en.wikipedia.org/wiki/List_of_American_Nobel_laureates"
    },
    {
      "title": "US Education System",
      "url": "https://united-states.education/us-education-system/"
    },
    {
      "title": "The Interstate Highway System - Definition, Purpose & Facts",
      "url": "https://www.history.com/topics/us-states/interstate-highway-system"
    },
    {
      "title": "50th Anniversary of the National System of Interstate and Defense Highways — Colorado Department of Transportation",
      "url": "https://www.codot.gov/about/CDOTHistory/50th-anniversary"
    },
    {
      "title": "Interstate Highway System",
      "url": "https://www.britannica.com/topic/Interstate-Highway-System"
    },
    {
      "title": "The Interstate Highway System — BriefHistory",
      "url": "https://briefhistory.us/places/infrastructure-transportation/interstate-highway-system"
    },
    {
      "title": "1 FREIGHT RAIL FACTS & FIGURES Freight Rail Safety •",
      "url": "https://www.aar.org/wp-content/uploads/2023/04/AAR-Facts-Figures-Fact-Sheet.pdf"
    },
    {
      "title": "Texas Interconnection",
      "url": "https://en.wikipedia.org/wiki/Texas_Interconnection"
    },
    {
      "title": "Weigh the Pros and Cons of Texas Grid Integration",
      "url": "https://www.bakerinstitute.org/research/weigh-pros-and-cons-texas-grid-integration"
    },
    {
      "title": "North American Electric Reliability Corporation",
      "url": "https://en.wikipedia.org/wiki/North_American_Electric_Reliability_Corporation"
    },
    {
      "title": "History of the Eisenhower Interstate System",
      "url": "https://www.fhwa.dot.gov/interstate-70th/history_eisenhower_interstate_system.cfm"
    },
    {
      "title": "Part I - History",
      "url": "https://highways.dot.gov/highway-history/interstate-system/dwight-d-eisenhower-system-interstate-and-defense-highways/part-i"
    },
    {
      "title": "Overview of America’s Freight Railroads Page 1 of 5 Summary",
      "url": "https://www.aar.org/wp-content/uploads/2018/08/Overview-of-Americas-Freight-RRs.pdf"
    },
    {
      "title": "Class I Railroad System Mileage and Ton-Miles of Freight: 1960-2022",
      "url": "https://www.bts.gov/browse-statistical-products-and-data/info-gallery/class-i-railroad-system-mileage-and-ton-miles-0"
    },
    {
      "title": "North American power transmission grid",
      "url": "https://en.wikipedia.org/wiki/North_American_power_transmission_grid"
    },
    {
      "title": "Mortality in the United States, 2024",
      "url": "https://cdc.gov/nchs/products/databriefs/db548.htm"
    },
    {
      "title": "CDC report shows US life expectancy rose in 2024",
      "url": "https://www.healio.com/news/primary-care/20260202/cdc-report-shows-us-life-expectancy-rose-in-2024"
    },
    {
      "title": "Mortality in the United States, 2024",
      "url": "https://www.cdc.gov/nchs/products/databriefs/db548.htm"
    },
    {
      "title": "Heart disease tops US mortality in 2024, CDC reports - McKnight's Long-Term Care News",
      "url": "https://www.mcknights.com/news/heart-disease-tops-us-mortality-in-2024-cdc-reports/"
    },
    {
      "title": "U.S. Health Care from Global Perspective 2026 Expanded Edition",
      "url": "https://www.commonwealthfund.org/publications/issue-briefs/2026/may/us-health-care-global-perspective-2026"
    },
    {
      "title": "US Health Spending Hits $4.8 Trillion, Insurance Coverage Peaks in 2023 Projections",
      "url": "https://www.ajmc.com/view/us-health-spending-hits-4-8-trillion-insurance-coverage-peaks-in-2023-projections"
    },
    {
      "title": "US: Health System Expenditures - World Health Systems Facts",
      "url": "https://healthsystemsfacts.org/the-us-health-system/us-health-system-expenditures/"
    },
    {
      "title": "Health Insurance Coverage Status ...",
      "url": "https://www.congress.gov/crs_external_products/IF/HTML/IF10830.web.html"
    },
    {
      "title": "US: Coverage and Access - World Health Systems Facts",
      "url": "https://healthsystemsfacts.org/the-us-health-system/us-health-system-coverage-and-costs-for-consumers/"
    },
    {
      "title": "Life expectancy in United States hits all-time high: CDC",
      "url": "https://thehill.com/policy/healthcare/5712651-life-expectancy-in-united-states-hits-all-time-high-cdc/"
    },
    {
      "title": "Ranked: The Top 10 Leading Causes of Death in the U.S.",
      "url": "https://www.visualcapitalist.com/americas-leading-causes-of-death/"
    },
    {
      "title": "www.cdc.gov",
      "url": "https://www.cdc.gov/nchs/data/databriefs/db548.pdf"
    },
    {
      "title": "U.S. Life Expectancy Hits Record High as Drug Overdose Deaths Decline in 2024",
      "url": "https://www.cdc.gov/nchs/pressroom/releases/20260129.html"
    },
    {
      "title": "Leading Causes of Death",
      "url": "https://www.cdc.gov/NCHS/FASTATS/LEADING-CAUSES-OF-DEATH.HTM"
    },
    {
      "title": "Cancer leading cause of death in 10 states: CDC",
      "url": "https://www.beckersoncology.com/oncology/leading-causes-of-death-in-every-state-cdc/"
    },
    {
      "title": "United States",
      "url": "https://www.commonwealthfund.org/international-health-policy-center/countries/united-states"
    },
    {
      "title": "The North Atlantic Treaty: U.S. Legal Obligations and Congressional Authorities",
      "url": "https://www.congress.gov/crs-product/LSB11256"
    },
    {
      "title": "International Community Responds",
      "url": "https://www.911memorial.org/learn/resources/digital-exhibitions/digital-exhibition-revealed-hunt-bin-laden/international-community-responds"
    },
    {
      "title": "U.S. Overseas Basing: Background and Issues for Congress",
      "url": "https://www.congress.gov/crs-product/R48123"
    },
    {
      "title": "29 Foreign Countries With the Largest US Military Presence - 24/7 Wall St.",
      "url": "https://247wallst.com/military/2025/10/27/29-foreign-countries-with-the-largest-us-military-presence/"
    },
    {
      "title": "US MILITARY PRESENCE AROUND THE WORLD - Lukmaan IAS Current Marathon (IR)",
      "url": "https://blog.lukmaanias.com/2026/04/29/us-military-presence-around-the-world/"
    },
    {
      "title": "July 1, 2026: Joint Review of USMCA to begin.",
      "url": "https://www.congress.gov/crs_external_products/IF/HTML/IF10997.web.html"
    },
    {
      "title": "USMCA 2026 Joint Review: United States declines to extend Agreement, triggering annual reviews",
      "url": "https://www.whitecase.com/insight-alert/usmca-2026-joint-review-united-states-declines-extend-agreement-triggering-annual"
    },
    {
      "title": "USMCA Joint Review: Process and Role of Congress",
      "url": "https://www.congress.gov/crs-product/R48787"
    },
    {
      "title": "USMCA Review 2026: Not Renewed, Still in Force",
      "url": "https://mayo.law/articles/updates/usmca-joint-review/"
    },
    {
      "title": "NATO has invoked Article 5 only once in its history",
      "url": "https://www.bushcenter.org/publications/nato-has-invoked-article-5-only-once-in-its-history"
    },
    {
      "title": "Federal Land Ownership: Overview and Data",
      "url": "https://www.congress.gov/crs-product/R42346"
    },
    {
      "title": "Federal land ownership by state - Ballotpedia",
      "url": "https://ballotpedia.org/Federal_land_ownership_by_state"
    },
    {
      "title": "Bureau Highlights",
      "url": "https://www.doi.gov/sites/default/files/documents/2025-06/fy26bibnps508.pdf"
    },
    {
      "title": "What is the Clean Water Act?",
      "url": "https://pacificlegal.org/what-is-the-clean-water-act/"
    },
    {
      "title": "history clean water act",
      "url": "https://www.epa.gov/laws-regulations/history-clean-water-act"
    },
    {
      "title": "The Clean Water Act: What to Know",
      "url": "https://www.lcmm.org/clean-water-act/what-to-know/"
    },
    {
      "title": "Discover the History of the Clean Water Act",
      "url": "https://epa.gov/laws-regulations/discover-history-clean-water-act"
    },
    {
      "title": "Federal land policy in Alaska - Ballotpedia",
      "url": "https://ballotpedia.org/Federal_land_policy_in_Alaska"
    },
    {
      "title": "Congressional Report Examines Federal Land Ownership and Management",
      "url": "https://legis1.com/news/federal-land-ownership-government-owns-roughly"
    },
    {
      "title": "Federal land sales, more logging and more oil revenue: What’s in the big federal bill for Alaska?",
      "url": "https://alaskabeacon.com/2025/06/19/federal-land-sales-more-logging-and-more-oil-revenue-whats-in-the-big-federal-bill-for-alaska/"
    },
    {
      "title": "Summary of the Clean Water Act",
      "url": "https://www.epa.gov/laws-regulations/summary-clean-water-act"
    },
    {
      "title": "Reflections and Exhortations on the Anniversary of the Clean Water Act",
      "url": "https://xerces.org/blog/clean-water-act-anniversary"
    },
    {
      "title": "Historically low water level in two crucial US reservoirs threatens water and power for millions",
      "url": "https://www.cnn.com/2026/07/22/climate/lake-mead-powell-record-low-water-colorado-river-drought"
    },
    {
      "title": "Management of the Colorado River: Water Allocations, Drought, and the Federal Role",
      "url": "https://www.congress.gov/crs-product/R45546"
    },
    {
      "title": "Colorado River Water Cuts, 2026: The 20% Reduction Measured Against What Is Left in Mead and Powell — reservoirs.earth",
      "url": "https://reservoirs.earth/the-reservoir/colorado-river-water-cuts-2026"
    },
    {
      "title": "Can the Colorado River Survive 2026?",
      "url": "https://www.sierraclub.org/sierra/can-colorado-river-survive-2026"
    },
    {
      "title": "Household Income in States and Metropolitan Areas: 2024",
      "url": "https://www.census.gov/library/publications/2025/acs/acsbr-025.html"
    },
    {
      "title": "Income in the United States: 2025",
      "url": "https://www.census.gov/library/publications/2026/demo/p60-289.html"
    },
    {
      "title": "Household Income in States and Metropolitan Areas: 2024",
      "url": "https://www2.census.gov/library/publications/2025/demo/acsbr-025.pdf"
    },
    {
      "title": "The Supreme Court's 'landmark decision' on tribal sovereignty",
      "url": "https://www.pbs.org/newshour/show/the-supreme-courts-landmark-decision-on-tribal-sovereignty"
    },
    {
      "title": "The Supreme Court’s attack on tribal sovereignty, explained - High Country News",
      "url": "https://www.hcn.org/articles/indigenous-affairs-justice-law-the-supreme-courts-attack-on-tribal-sovereignty-explained/"
    },
    {
      "title": "Tribal Sovereignty and Jurisdiction in Wisconsin",
      "url": "https://docs.legis.wisconsin.gov/misc/lc/information_memos/2026/im_2026_03"
    },
    {
      "title": "2026 Tribal Sovereignty and Jurisdiction News Stories, Indian Law Bulletins; National Indian Law Library, Native American Rights Fund",
      "url": "https://www.narf.org/nill/bulletins/news/2026/sovereignty.html"
    }
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/"
}