Washington, D.C., became the permanent capital of the United States in 1800.
The Constitution authorized a federal district that would not belong to any state. The Residence Act of 1790 selected a site on the Potomac River, and President George Washington oversaw the creation of the new capital. The district was named for Washington, while the city was planned in part by French engineer Pierre Charles L’Enfant.
The federal government moved from Philadelphia to Washington in June 1800. President John Adams became the first president to live in the Executive Mansion, later called the White House, and Congress met in the unfinished Capitol.
Philadelphia had served as the national capital before the move, while New York City was the first capital under the Constitution. Washington, D.C., is a federal district rather than a state, and Congress has ultimate authority over its local government under the Constitution’s District Clause.