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 semi-exclavic state of Alaska in the northwest and the archipelagic state of Hawaii 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 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 first settlement of the Thirteen Colonies in Virginia in 1607. Intensive agriculture in the rapidly expanding Southern Colonies encouraged 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 on July 4, 1776. The U.S. emerged victorious from the American Revolutionary War of 1775 to 1783 and expanded westward across North America, dispossessing Native Americans during the Indian Wars.