USA Wallpaper - Flag usa-united states

The United States of America (USA), commonly known as the United States (U.S. or US) or America, is a country comprising 50 states, a federal district, five major self-governing territories, and various possessions.[i] At 3.8 million square miles (9.8 million km2), the United States is the world's third or fourth largest country by total area[d] and is slightly smaller than the entire continent of Europe, which is 3.9 million square miles (10.1 million km2). With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the most populous city is New York City. Most of the country is located contiguously in North America between Canada and Mexico.

Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago.[20] European colonization began in the 16th century. The United States emerged from the thirteen British colonies established along the East Coast. Following the French and Indian War, numerous disputes between Great Britain and the colonies led to the American Revolution, which began in 1775, and the Declaration of Independence in 1776. The war ended in 1783 with the United States becoming the first country to gain independence from a colonial empire.[21] The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties. The United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories,[22] displacing Native American tribes, and gradually admitting new states until it spanned the continent by 1848.

During the second half of the 19th century, the Civil War led to the abolition of slavery.[23][24] By the end of the century, the United States had reached the Pacific Ocean,and its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power. The United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, and a permanent member of the United Nations Security Council. Sweeping civil rights legislation passed under President Lyndon B. Johnson, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color and established the country as a full liberal democracy.[27] During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U.S. Moon landing. The end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower.

The United States is the world's oldest surviving federation. It is a federal republic and a representative democracy. The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States (OAS), and other international organizations. The United States is a highly developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for approximately a quarter of global GDP.[29] The U.S. economy is largely post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world.[30] The United States is the world's largest importer and the second-largest exporter of goods, by value.[31][32] Although its population is only 4.3% of the world total,[33] the U.S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country.