when did the capital move to washington dc
History of Washington, D.C. In 1800, the seat of government was finally moved to the new city, and on February 27, 1801, the District of Columbia Organic Act of 1801 placed the District under the jurisdiction of Congress. The act also organized the unincorporated territory within the District into two counties: the County of Washington on the northeast bank of the Potomac, and the County of Alexandria on the southwest bank. On May 3, 1802, the City of Washington was granted a municipal government consisting of a mayor appointed by the President of the United States.