the capital of the world
Washington, DC is a city. DC represents the name District of Columbia. Washington is the name of the city.
Nick Altrock died January 20, 1965, in Washington, DC, USA.
Nick Young died October 31, 1916, in Washington, DC, USA.
One of them is the Washington Post
George Washington University in Washington DC.
Washington DC
In September of 1791.
Washington, DC
The Washington Monument is in Washington DC.
The Evergreen state
Washington DC is the name of a place, which means it is a proper noun.Proper nouns are the names of specific people (George Washington, Marie Antoinette), the names of specific places (Washington DC, Japan), or specific things (Oreo, Toyota Prius).
Washington DC is not a state. It is a city. DC, however, is a District. Hence the name District of Columbia.