The United States of America (also known as the United States, the U.S., the U.S.A., the U.S. of A., and America) is a country in North America that extends from the Atlantic Ocean to the Pacific Ocean and shares land borders with Canada and Mexico and a sea border with Russia. The United States is a federal republic, with its capital in Washington, D.C.
The present-day continental United States has been inhabited for at least 15,000 years by indigenous tribes.After European exploration and settlement in the 16th century, the English established their own colonies—and gained control of others that had been begun by other European nations—in the eastern portion of the continent in the 17th and early 18th centuries. On July 4, 1776, at war with Britain over fair governance, thirteen of these colonies declared their independence. In 1783, the war ended in British acceptance of the new nation. Since then, the United States of America has more than quadrupled in size: it now consists of 50 states and one federal district; it also has numerous overseas territories.