<P> On July 9, 1790, Congress passed the Residence Act, which approved the creation of a national capital on the Potomac River . The exact location was to be selected by President George Washington, who signed the bill into law on July 16 . Formed from land donated by the states of Maryland and Virginia, the initial shape of the federal district was a square measuring 10 miles (16 km) on each side, totaling 100 square miles (259 km). </P> <P> Two pre-existing settlements were included in the territory: the port of Georgetown, Maryland, founded in 1751, and the city of Alexandria, Virginia, founded in 1749 . During 1791--92, Andrew Ellicott and several assistants, including a free African American astronomer named Benjamin Banneker, surveyed the borders of the federal district and placed boundary stones at every mile point . Many of the stones are still standing . </P> <P> A new federal city was then constructed on the north bank of the Potomac, to the east of Georgetown . On September 9, 1791, the three commissioners overseeing the capital's construction named the city in honor of President Washington . The federal district was named Columbia, which was a poetic name for the United States commonly in use at that time . Congress held its first session in Washington on November 17, 1800 . </P> <P> Congress passed the Organic Act of 1801, which officially organized the District and placed the entire territory under the exclusive control of the federal government . Further, the unincorporated area within the District was organized into two counties: the County of Washington to the east of the Potomac and the County of Alexandria to the west . After the passage of this Act, citizens living in the District were no longer considered residents of Maryland or Virginia, which therefore ended their representation in Congress . </P>

Where does the term district of columbia come from