United States

The United States of America (USA), also known as the United States (U.S.) or America, is a country located primarily in North America. It is a federal republic of 50 states and the federal capital district of Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the state of Alaska forming a semi-exclave in the northwest and the state of Hawaii spanning an archipelago in Oceania. Indian country includes 574 federally recognized tribes and 326 Indian reservations with tribal sovereignty rights. The U.S. asserts sovereignty over five major island territories and various uninhabited islands in the Pacific Ocean and the Caribbean. It is an ecologically megadiverse country, with the world's third-largest land area, the United States is the third-largest country in the world by land area, behind Russia and China. By total area (land and water), it is the third-largest, behind Russia and Canada, if its coastal and territorial water areas are included. However, if only its internal waters are included (bays, sounds, rivers, lakes, and the Great Lakes), the U.S. is the fourth-largest, after Russia, Canada, and China.
Coastal/territorial waters included:
Only internal waters included: |name=largestcountry}} and third-largest population, exceeding 340 million.

Paleo-Indians migrated to North America across the Bering land bridge more than 12,000 years ago, and formed various cultures. Spanish Florida, the first European colony in what is now the continental U.S., was established in 1513, and later British colonization led to the settlement of the Thirteen Colonies beginning with Virginia in 1607. The agriculture-reliant economy of the Southern Colonies became dependent on the enslavement of Africans. Clashes with the British Crown over taxation and political representation sparked the American Revolution, with the Second Continental Congress formally declaring independence for the United States (U.S.) on July 4, 1776. The U.S. emerged victorious from the American Revolutionary War of 1775 to 1783 with significant territorial gains, and expanded westward across North America, dispossessing Native Americans during the Indian Wars. The Louisiana Purchase in 1803 and the end of the Mexican–American War in 1848 saw additional significant territorial acquisition. As more states were admitted, a North–South division over the expansion of slavery led to the Confederate States of America that depended on it declaring secession from the the Union, resulting in the American Civil War of 1861 to 1865. With the defeat of the Confederacy the nation reunified and slavery was abolished. In the late 19th and early 20th centuries, the U.S. established itself as a great power following the Spanish–American War and World War I. After Japan's attack on Pearl Harbor in 1941, the U.S. entered World War II; its aftermath left the U.S. and the Soviet Union as the world's superpowers. During the Cold War, both countries struggled for ideological dominance and international influence. The Soviet Union's collapse and the end of the Cold War in 1991 left the U.S. as the world's sole superpower.

The U.S. national government, as established by the Constitution in 1789, is a presidential republic and liberal democracy with a separation of powers into three branches: legislative, executive, and judicial. The U.S. Congress, the national legislature, is composed of the House of Representatives (a lower house based on population) and the Senate (an upper house based on equal representation for each state). The U.S. federal system provides substantial autonomy to the 50 states; although the United States Constitution is the supreme law, each state has its own constitution and laws compatible with it. The American political tradition is rooted in Enlightenment ideals of liberty, equality, individual rights, and the rule of law. Since the 1850s, the Democratic and Republican parties have dominated American politics.

A developed country, the U.S. ranks high in economic competitiveness, productivity, innovation, and higher education. The U.S. accounted for over a quarter of nominal global economic output in 2024, and its economy has been the world's largest by nominal GDP since about 1890. It possesses the most wealth of any country and has the highest disposable household income per capita among OECD countries, though U.S. wealth inequality is one of the most pronounced in those countries. A melting pot of many ethnicities and customs, the culture of the U.S. has been shaped by centuries of immigration, and its soft power influence has a global reach. The U.S. is a member of multiple international organizations and plays a leading role in global political, cultural, economic, and military affairs. Provided by Wikipedia