The flag of the District of Columbia was introduced on 15th of October in 1938. It shows a white bunting with two down moved red stripes and above three five-pointed red stars. The design of the flag dates back to the family arms of the family of General George Washington, which is detectable in England from 1592.
The name "Columbia" dates back to the name of Christopher Columbus. It is a poetic and allegorical term for the american continent from the 18th Century, but over time it came out of fashion. Similar names are Germania, Britannia, Borussia or Saxonia. Similar columbia-names in America are: Colombia (State) or British Columbia (Province of Canada).