Both Virginia and Maryland gave up land for the nation's capitol. So, technically Washington DC is not in a state at all, though it is surrounded by Maryland's borders.
Washington,DC (District of Columbia)
The abbreviation "DC" is postponed to "Washington" for two important resasons: [i] for locative indication of "District of Columbia"; and [ii] to distinguish Washington Sate of Washington City, the 42nd of the United Satate.
The state of Washington.
The abbreviation for Washington state in the United States is WA.
Washington dc is not a state.
Washington, DC
Washington DC
There were two weak tornadoes in the sate of Washington in 2010.
Washington - Baltimore Washington International, DC, USA (BWI) Washington - Washington - All Airports, DC, USA (WAS) Washington - Ronald Reagan National Airport, DC, USA (DCA) Washington - Washington Dulles, DC, USA (IAD)
there are no counties in Washington DC because Washington DC is a city itself.
Washington DC
Washington, DC