Paleo-Indians migrated from Eurasia to what is now the U.S. mainland at least 15,000 years ago, with European colonization beginning in the 16th century. The United States emerged from 13 British colonies along the East Coast. Disputes between Great Britain and the colonies led to the American Revolution. On July 4, 1776, as the colonies were fighting Great Britain in the American Revolutionary War, delegates from the 13 colonies unanimously adopted the Declaration of Independence. The war ended in 1783 with recognition of the independence of the United States by the Kingdom of Great Britain, and was the first successful war of independence against a European colonial empire. The country's constitution was adopted on September 17, 1787, and ratified by the states in 1788. The first ten ame