District of Columbia vs Washington, D.C.

District of Columbia

name

  • The federal capital region of the United States of America. The City of Washington used to be a municipality within the District of Columbia until 1871, when two entities were merged. For this reason, the district is also generally known as Washington, D.C. 

Washington, D.C.

name

  • The capital city of the United States, formally known as the District of Columbia. Abbreviated as D.C. or DC. 

How often have the words District of Columbia and Washington, D.C. occurred in a corpus of books? (source: Google Ngram Viewer )