Also known as Washington, D.C., the District of Columbia is the capital city of the United States of America. By U.S. law, Washington, D.C. is not part of a state and is under the direct authority of the federal government.
Prior to the foundation of Washington, D.C., each of the cities in which Congress met for a session is considered to have briefly been the nation's capital. The list begins with the First Continental Congress in Philadelphia in 1774. The Residence Act of 1790 provided for the establishment of Washington, D.C., on the Potomac River from land donated by Maryland and Virginia.