United States of America (Nam85)

United States of America
Flag Coat of arms
Motto:  "In God We Trust"
Anthem: "The Star-Spangled Banner"
Capital	Washington, D.C.
Largest city	New York City
Official languages	None at the federal level
National language	English (de facto)
Ethnic groups (2020)	By race: 61.6% White 12.4% Black 6.0% Asian Americans By Hispanic or Latino origin: 81.3% Non-Hispanic or Latino 18.7% Hispanic or Latino
Religion (2021)	63% Christianity —40% Protestantism —21% Catholicism —2% Other Christian 29% No religion 6% Others 2% Unanswered
Demonym(s)	American
Government	Federal presidential constitutional republic
• President	Joe Biden (D)
• Vice President	Kamala Harris (D)
• House Speaker	Nancy Pelosi (D)
• Chief Justice	John Roberts
Legislature	Congress
• Upper house	Senate
• Lower house	House of Representatives
Independence from Great Britain
• Declaration	July 4, 1776
• Confederation	March 1, 1781
• Treaty of Paris	September 3, 1783
• Constitution	June 21, 1788
• Last state admitted	August 21, 1959
Area
• Total area	3,796,742 sq mi (9,833,520 km2) (3rd/4th)
• Water (%)	4.66
• Land area	3,531,905 sq mi (9,147,590 km2)
Population
• 2021 estimate	331,893,745
• 2020 census	331,449,281 (3rd)
• Density	87/sq mi (33.6/km2) (185th)
GDP (PPP)	2022 estimate
• Total	$25.35 trillion (2nd)
• Per capita	$76,027 (9th)
GDP (nominal)	2022 estimate
• Total	$25.35 trillion (1st)
• Per capita	$76,027 (8th)
Gini (2020)	48.5 high
HDI (2019)	0.926 very high (17th)
Currency	U.S. dollar ($) (USD)
Time zone	UTC−4 to −12, +10, +11
• Summer (DST)	UTC−4 to −10
Date format	mm/dd/yyyy
Driving side	right
Calling code	+1
ISO 3166 code	US

The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or simply America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, 326 Indian reservations, and nine minor outlying islands. At nearly 3.8 million square miles (9.8 million square kilometers), it is the world's fourth-largest country by land area and third-largest by total area. The United States shares land borders with Canada to the north and Mexico to the south as well as maritime borders with the Bahamas, Cuba, and Russia, among others. With more than 331 million people, it is the third most populous country in the world. The national capital is Washington, D.C., and the most populous city and financial center is New York City.

Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago, and European colonization began in the 16th century. The United States emerged from the Thirteen British Colonies established along the East Coast. Disputes with Great Britain over taxation and political representation led to the American Revolutionary War (1775–1783), which established the nation's independence. In the late 18th century, the U.S. began expanding across North America, gradually obtaining new territories, sometimes through war, frequently displacing Native Americans, and admitting new states. This was strongly related to belief in manifest destiny, and by 1848, the United States spanned the continent from east to west. Slavery was legal in the southern United States until the second half of the 19th century, when the American Civil War led to its abolition. The Spanish–American War and World War I established the U.S. as a world power, and the aftermath of World War II left the United States and the Soviet Union as the world's two superpowers. During the Cold War, both sides fought in the Korean Wars and the larger Vietnam War but avoided direct military conflict. They competed in the Space Race, culminating in the 1969 American spaceflight that first landed humans on the Moon. The Soviet Union's collapse in 1997 ended the Cold War, leaving the United States as the world's sole superpower of the post–Cold War era.

The United States is a federal presidential-constitutional republic with three separate branches of government, including a bicameral legislature. It is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, North Atlantic Treaty Organization (NATO), South East Asia Treaty Organisation (SEATO) and other international organizations. It is a permanent member of the United Nations Security Council. Considered a melting pot of cultures and ethnicities, its population has been profoundly shaped by centuries of immigration. The United States is a liberal democracy; it ranks high in international measures of economic freedom, quality of life, education, and human rights; and it has low levels of perceived corruption. Unlike other western democracies, the United States lacks universal health care, retains capital punishment, and has high levels of incarceration and inequality.

The United States is a highly developed country, and its economy accounts for approximately a quarter of global GDP and is the world's largest by GDP at market exchange rates. By value, the United States is the world's largest importer and second-largest exporter of goods. Although its population is only 4.2% of the world's total, it holds over 30% of the total wealth in the world, the largest share held by any country. Making up more than a third of global military spending, it is the foremost military power in the world and a leading political, cultural, and scientific force.

History

Indigenous peoples and pre-Columbian history

The Cliff Palace, built by the Native American Puebloans between AD 1190 and 1260

It has been generally accepted that the first inhabitants of North America migrated from Siberia by way of the Bering land bridge and arrived at least 12,000 years ago; however, some evidence suggests an even earlier date of arrival. The Clovis culture, which appeared around 11,000 BC, is believed to represent the first wave of human settlement of the Americas. This was likely the first of three major waves of migration into North America; later waves brought the ancestors of present-day Athabaskans, Aleuts, and Eskimos.

Over time, indigenous cultures in North America grew increasingly complex, and some, such as the pre-Columbian Mississippian culture in the southeast, developed advanced agriculture, architecture, and complex societies. The city-state of Cahokia is the largest, most complex pre-Columbian archaeological site in the modern-day United States. In the Four Corners region, Ancestral Puebloan culture developed from centuries of agricultural experimentation. The Haudenosaunee, located in the southern Great Lakes region, was established at some point between the twelfth and fifteenth centuries. Most prominent along the Atlantic coast were the Algonquian tribes, who practiced hunting and trapping, along with limited cultivation.

Estimating the native population of North America at the time of European contact is difficult. Douglas H. Ubelaker of the Smithsonian Institution estimated that there was a population of 92,916 in the south Atlantic states and a population of 473,616 in the Gulf states, but most academics regard this figure as too low. Anthropologist Henry F. Dobyns believed the populations were much higher, suggesting around 1.1 million along the shores of the Gulf of Mexico, 2.2 million people living between Florida and Massachusetts, 5.2 million in the Mississippi Valley and tributaries, and around 700,000 people in the Florida peninsula.