WordNet (r) 3.0 (2006):

District of Columbia
    n 1: the district occupied entirely by the city of Washington;
         chosen by George Washington as the site of the capital of
         the United States and created out of land ceded by Maryland
         and Virginia [syn: District of Columbia, D.C., DC]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

DISTRICT OF COLUMBIA. The name of a district of country, ten miles square,
situate between the states of Maryland and Virginia, over which the national
government has exclusive jurisdiction. By the constitution, congress may "
exercise exclusive jurisdiction in all cases whatsoever, over such district,
not exceeding ten miles square, as may, by, cession of particular states,
and the acceptance of congress, become the seat of government of the United
States." In pursuance of this authority, the states of Maryland and
Virginia, ceded to the United States, a small territory on the banks of the
Potomac, and congress, by the Act of July 16, 1790, accepted the same for
the permanent seat of the government of the United States. The act provides
for the removal of the seat of government from the city of Philadelphia to
the District of Columbia, on the first Monday of December, 1800. It is also
provided, that the laws of the state, within such district, shall not be
affected by the acceptance, until the time fixed for the removal of the
government thereto, and until congress shall otherwise by law provide.
     2. It seems that the District of Columbia, and the territorial
districts of the United States, are not states within the meaning of the
constitution, and of the judiciary act, so as to enable a citizen thereof to
sue a citizen of one of the states in the federal courts. 2 Cranch, 445; 1
Wheat, 91.
     3. By the Act of July 11, 1846, congress retroceded the county of
Alexandria, part of the District of Columbia, to the state of Virginia.



U.S. Gazetteer Counties (2000):

District of Columbia -- U.S. County in District of Columbia
   Population (2000):    572059
   Housing Units (2000): 274845
   Land area (2000):     61.403254 sq. miles (159.033692 sq. km)
   Water area (2000):    6.937868 sq. miles (17.968995 sq. km)
   Total area (2000):    68.341122 sq. miles (177.002687 sq. km)
   Located within:       District of Columbia (DC), FIPS 11
   Location:             38.913611 N, 77.013222 W
   Headwords:
    District of Columbia
    District of Columbia, DC