The United States of America (USA), generally known as the United States (U.S. or on the other hand US), the States or essentially America, is a nation containing 50 expresses, a government region, five significant self-overseeing domains, and different belongings. At 3.8 million square miles (9.8 million km2), it is the world's third or fourth-biggest nation by complete area[d] and is somewhat littler than the whole mainland of Europe. The greater part of the nation is situated in focal North America among Canada and Mexico. With an expected populace of more than 328 million individuals, the U.S. is the third most crowded nation. The capital is Washington, D.C., and the most crowded city is New York City.

Paleo-Indians relocated from Siberia toward the North American terrain in any event 12,000 years back. European colonization started in the sixteenth century. The United States rose up out of the thirteen British settlements set up along the East Coast. Various debates between Great Britain and the states prompted the American Revolutionary War enduring somewhere in the range of 1775 and 1783, prompting autonomy. The United States set out on a lively development crosswise over North America all through the nineteenth century—continuously obtaining new regions, dislodging Native Americans, and conceding new states—until by 1848 it traversed the landmass. During the second 50% of the nineteenth century, the American Civil War prompted the annulment of subjection in the United States. The Spanish–American War and World War I affirmed the nation's status as a worldwide military power.

The United States rose up out of World War II as a worldwide superpower. It was the main nation to create atomic weapons, and the just one to utilize them in fighting. During the Cold War, the United States and the Soviet Union contended in the Space Race, coming full circle with the 1969 Apollo 11 strategic, spaceflight that originally landed people on the Moon. The finish of the Cold War and breakdown of the Soviet Union in 1991 remaining the United States as the world's sole superpower.

The United States is a government republic and a delegate majority rules system. It is an establishing individual from the United Nations, World Bank, International Monetary Fund, Organization of American States (OAS), NATO, and other worldwide associations. It is a lasting individual from the United Nations Security Council.

An exceptionally created nation, the United States is the world's biggest economy by ostensible GDP, the second-biggest by acquiring power equality, and records for around a fourth of worldwide GDP. The United States is the world's biggest merchant and the second-biggest exporter of merchandise, by esteem. Despite the fact that its populace is 4% of the world aggregate, it holds 31% of the absolute riches on the planet, the biggest portion of worldwide riches amassed in a solitary nation. In spite of salary and riches inconsistencies, the United States keeps on positioning high in proportions of financial execution, including normal compensation, middle pay, middle riches, human improvement, per capita GDP, and laborer efficiency. It is the premier military power on the planet, making up in excess of 33% of worldwide military spending, and is a main political, social, and logical power globally.