The nation’s capital dates back to 1791, when President George Washington declared 100 square miles of Maryland and Virginia as the capital. The name honored the president and Columbus (D.C. which stands for District of Columbia, a common Revolutionary nickname).
Since then, 31 of the original miles have been returned to Virginia, and the name is being reconsidered. As congress considers making DC a state, they are also considering a name change.
Aligning with more modern thinking, the D.C. would stand for Douglass Commonwealth to honor Frederick Douglass the abolitionist and national reformer as part of the new name.
– Rebecca Hastings, The Washington DC 100