'There have been nine U.S. capitals.'
Although Washington, D.C., has been the established U.S. capital since 1800, eight other cities have served as the temporary seat of government, depending on the location of Congress. These are Philadelphia, Baltimore, Lancaster, York, Princeton, Annapolis, Trenton, and New York. Post-Constitution, the Congress as it exists in its present form has convened in Philadelphia, New York and Washington, D.C.