The United States occupies a total area of approximately 3,809,525 square miles (9,866,632 square kilometers), including inland water and its share of the Great Lakes, with a land area of 3,531,837 square miles (9,147,420 square kilometers).¹³ The 48 contiguous states span central North America between the Atlantic Ocean to the east and the Pacific Ocean to the west, bordered by Canada to the north and Mexico and the Gulf of Mexico to the south.¹⁴ The United States-Canada land border is the longest international border shared by two nations. Separated from the contiguous states by Canada, Alaska occupies 663,268 square miles (1,717,856 square kilometers) in northwestern North America, bordering the Pacific and Arctic oceans and separated from Russia by the Bering Strait. The state of Hawaii is a volcanic archipelago encompassing 10,931 square miles (28,311 square kilometers) in the central Pacific Ocean. The country also holds maritime borders with the Bahamas and Cuba.

Moving from east to west across the mainland, the physical landscape transitions from an Atlantic coastal plain to the rolling, forested Appalachian Mountains and the Ozarks. West of the Appalachians lies a vast interior plain encompassing the agricultural heartland of the Midwest and the Great Plains.¹⁵ Much of this interior is drained by the Mississippi-Missouri river system, while the Great Lakes along the northern border form the world's largest group of freshwater lakes by total area. Farther west rise the rugged ranges of the North American Cordillera, including the Rocky Mountains, the Great Basin, the Sierra Nevada, and the Cascade Range.¹⁶ Major western waterways include the Colorado, Columbia, and Rio Grande rivers. Alaska's Denali, at 20,310 feet, is the highest peak in the country and North America, while Mount Whitney in California is the highest peak in the contiguous states, and California's Death Valley is the lowest point.

Because of its size and topographic variety, the United States encompasses nearly every major climate zone.¹⁷ When moist air from the Pacific Ocean encounters the Sierra Nevada and Cascades, it releases heavy precipitation on western windward slopes—supporting temperate rainforests in the Pacific Northwest—while creating a rain shadow that leaves the Great Basin and Southwestern deserts, such as the Mojave and Sonoran, arid. The eastern half of the country ranges from humid continental in the north to humid subtropical along the Gulf and south Atlantic coasts, while Alaska features subarctic tundra and glaciers, and Hawaii experiences a tropical climate. Accounting for roughly 13 percent of the world's endemic biodiversity, the country faces ongoing environmental stresses from land conversion, pollution, invasive species, and climate change, which have altered seasonal patterns, increased drought risks in the West, and threatened freshwater ecosystems in the Midwest and Great Lakes.¹⁸

The United States is a federal republic in which sovereignty is shared between the national government and the governments of the 50 individual states. Under the Tenth Amendment to the Constitution, powers not delegated to the federal government nor prohibited to the states are reserved to the states or the people. Each state maintains its own written constitution, elected governor, legislature, and judiciary. Outside the 50 states and the federal district of Washington, D.C., the United States exercises sovereignty over five populated unincorporated territories—Puerto Rico and the U.S. Virgin Islands in the Caribbean, and Guam, the Northern Mariana Islands, and American Samoa in the Pacific—along with nine minor outlying islands, one of which, Palmyra Atoll, is an incorporated territory. Additionally, the country maintains Compacts of Free Association with three sovereign Pacific nations: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau.

At the national level, the Constitution establishes a system of checks and balances across three separate branches of government. The legislative branch is the bicameral Congress, comprising the Senate and the House of Representatives. The Senate has 100 members, with each state electing two senators to ensure equal representation, while the House of Representatives consists of 435 voting members apportioned among the states according to population as determined by the decennial census. The executive branch is headed by the president, who serves as both head of state and head of government, alongside the vice president and a Cabinet of 15 department secretaries.¹⁹²⁰ The judicial branch is led by the Supreme Court and lower federal courts, which interpret the Constitution and federal laws.

American politics operates under a two-party system dominated by the Democratic Party and the Republican Party.²¹ Under the Presidential Succession Act of 1947 and the 25th Amendment, if the presidency becomes vacant, the office passes to the vice president, followed in the line of succession by the speaker of the House of Representatives, the president pro tempore of the Senate, and the Cabinet secretaries in the order of their departments' creation, beginning with the secretary of state. In the 119th Congress (2025–2027), Republican Donald Trump serves as president, with JD Vance as vice president and Republican Mike Johnson of Louisiana serving as speaker of the House after winning re-election on January 3, 2025, by a 218–215 margin over Democratic leader Hakeem Jeffries.²² Legislative activity in 2025 and 2026 has centered on budget reconciliation packages, tax and spending changes, border security, and energy infrastructure for data centers.²³²⁴

The United States exerts broad diplomatic, economic, and security influence across the globe.²⁵ It is a founding member of the United Nations, the International Monetary Fund (which it joined in December 1945), the World Bank, and the North Atlantic Treaty Organization (NATO).²⁶²⁷ It also participates in major multilateral groupings including the Group of Seven (G7), the Group of Twenty (G20), the Organisation for Economic Co-operation and Development (OECD), the World Trade Organization (WTO), the Asia-Pacific Economic Cooperation (APEC) forum, and the United States–Mexico–Canada Agreement (USMCA). Beyond the 31 other member states of NATO in Europe and North America, the United States maintains formal bilateral defense treaties with Indo-Pacific allies including Japan, South Korea, Australia, the Philippines, and Thailand.

To complement its diplomatic posture, the federal government allocates substantial resources to foreign assistance and defense trade.²⁸ In fiscal year 2024, the United States committed approximately $82.3 billion in foreign aid, accounting for 1.2 percent of the federal budget, with roughly two-thirds directed toward economic development and one-third toward military assistance. Under the Arms Export Control Act, the country is also the world's leading supplier of military equipment; in fiscal year 2025, total defense trade—combining government-to-government Foreign Military Sales of $104.38 billion and licensed Direct Commercial Sales—reached $331.18 billion.

The United States Armed Forces are overseen by the civilian-led Department of Defense, with the president acting as commander-in-chief. As of September 2025, the military comprised approximately 2.1 million active-duty and reserve personnel across its service branches, with the Army serving as the largest branch, representing 34 percent of active-duty troops and 65 percent of reservists. By absolute expenditure, the United States leads the world in military spending by a wide margin. Depending on accounting definitions, federal discretionary defense outlays totaled $893 billion to $919.2 billion in fiscal year 2025—roughly 13 percent of the federal budget—while broader international estimates by the Stockholm International Peace Research Institute (SIPRI), which include military retirement and related international outlays, placed 2025 U.S. military spending at $954 billion. That figure represented 33 percent of all global military expenditures, exceeding the combined defense budgets of the next six highest-spending nations.

The United States possesses a highly developed, diversified mixed-market economy that is the largest in the world by nominal gross domestic product (GDP) and the second-largest when adjusted for purchasing power parity (PPP). Generating roughly 26 percent of total global economic output, the nation's nominal GDP reached approximately $32.38 trillion to $32.64 trillion in 2026, with a nominal GDP per capita of roughly $94,430 to $95,212, ranking ninth or tenth globally.²⁹³⁰ The service sector dominates economic activity, accounting for 76.4 percent of GDP, followed by industry at 17.6 percent and agriculture at 5.9 percent. Household consumption makes up 67.9 percent of GDP, alongside fixed capital investment at 17.5 percent and government consumption at 17.3 percent.

Driven by abundant natural resources, extensive transportation infrastructure, and high labor productivity, the United States is among the world's foremost producers of petroleum, natural gas, coal, copper, gold, and zinc, as well as the leading global exporter of agricultural food products. Its industrial sector manufactures motor vehicles, aerospace equipment, chemicals, steel, electronics, and computers. New York City serves as the world's principal financial center and largest metropolitan economy, while the United States dollar functions as the premier global reserve currency and the standard benchmark for international commodities and finance. By value, the country is the world's largest importer and second-largest exporter of goods and services, and it serves as home to 139 of the world's 500 largest companies by revenue.

According to the International Monetary Fund (IMF), the U.S. economy grew by 2.0 percent in 2025 despite a fourth-quarter federal government shutdown, tariff shifts, and reduced immigration inflows, with real GDP growth projected at 2.3 to 2.4 percent in 2026 and unemployment holding near 4 percent. While American households recorded the highest median household income among OECD member nations in 2026 and the country holds the world's largest number of billionaires, the United States also exhibits one of the widest rates of income and wealth inequality among developed economies.³¹ Persistent fiscal imbalances remain a central macroeconomic challenge: the federal fiscal deficit stood at 5.9 percent of GDP in fiscal year 2025, while general government gross debt reached 123.9 percent of GDP, which the IMF projects will exceed 140 percent by 2031 following 2025 tax and spending legislation.

According to the U.S. Census Bureau's Vintage 2025 estimates, the resident population of the 50 states and Washington, D.C., stood at 341,784,857 on July 1, 2025, up from 331,449,281 at the 2020 decennial census. An additional 3.6 million people reside in the five populated unincorporated territories, primarily in Puerto Rico, which has a population of roughly 3.29 million. Between July 2024 and July 2025, annual population growth slowed to 0.5 percent (1.8 million people), down from 1.0 percent (3.2 million people) the prior year.³² This deceleration was driven by a record-low total fertility rate of approximately 1.6 births per woman—well below the 2.1 replacement rate—and a 53.8 percent drop in net international migration, which fell from 2.7 million in 2023–2024 to 1.3 million in 2024–2025. Overall life expectancy stood at 79.0 years in 2024 (76.5 years for males and 81.4 years for females).

The population is highly urbanized, with roughly 83 percent of residents living in urban and metropolitan areas and an overall population density of about 96.8 people per square mile (37.4 per square kilometer). Geographically, population growth in recent decades has shifted toward the South and West, although the Midwest recorded positive net domestic migration in 2024–2025 for the first time in the 2020s. California is the most populous state at roughly 39.4 million residents, followed by Texas at 31.3 million, Florida at 23.4 million, and New York at 20 million; Pennsylvania, Illinois, Ohio, Georgia, North Carolina, and Michigan also exceed 10 million residents. New York City is the nation's most populous municipality.

Shaped by centuries of Indigenous habitation, forced African migration, and global immigration, the United States is racially and ethnically diverse. In the 2020 census, racial composition was 61.6 percent White, 12.4 percent Black or African American, 6.0 percent Asian, 2.9 percent Native American or Alaska Native, 0.2 percent Pacific Islander, 10.2 percent multiracial, and 8.4 percent other races, while Hispanic and Latino Americans of any race constitute a rapidly growing share that makes up roughly half of the population in the South and West. The foreign-born share of the population more than tripled from an all-time low of 4.7 percent in 1970 to 14.8 percent in 2024, while the share of Americans aged 65 and older nearly doubled over the same period from 10 percent to 18 percent. Under Census Bureau projections, the national population is expected to peak near 369 million around 2080 before gradually declining.

American society and culture have been forged through the blending of Indigenous traditions, European political and legal institutions, African cultural expressions, and continuous immigration from Latin America, Asia, and the rest of the world.³³ English is the predominant language spoken across the country and was designated the official language of the federal government under Executive Order 14224, while Spanish is the second most widely spoken language. The First Amendment to the Constitution guarantees freedom of religion and prohibits the establishment of a national church. Christianity remains the largest religion—encompassing diverse Protestant denominations, Roman Catholicism, and Eastern Orthodoxy—alongside substantial communities practicing Judaism, Islam, Buddhism, and Hinduism, as well as a growing proportion of religiously unaffiliated residents.

Over the past half-century, family structures and educational attainment in the United States have undergone marked shifts. Americans marry at lower rates and at later ages than in previous generations, while the expanded participation of women in higher education and the professional workforce since the 1970s has reshaped household economics and labor dynamics. Primary and secondary education is compulsory and administered primarily by state and local governments, funded through local property and state taxes, while the country's higher education system includes thousands of public and private colleges and research universities that attract students and scholars globally.

Healthcare in the United States is delivered through a mixed system of private insurance, employer-sponsored coverage, and public programs such as Medicare and Medicaid, overseen at the federal level by the Department of Health and Human Services.³⁴ Because medical professionals serve an increasingly multicultural and multilingual population across both metropolitan and rural areas, accrediting bodies such as the Liaison Committee on Medical Education and the American Association of Colleges of Nursing mandate cultural competency training, while federal agencies promote National Standards for Culturally and Linguistically Appropriate Services to address persistent racial and socioeconomic disparities in health outcomes.³⁵³⁶ Beyond domestic institutions, American popular culture—spanning cinema, popular music, literature, digital media, cuisine, and organized sports—is exported worldwide, serving as a major component of the nation's global soft power.