District vs Mainland

District

name
  • The District of Columbia, the federal district of the United States. 

  • The District Line of the London Underground, originally known as the District Railway. 

  • Any of numerous governmental districts. 

Mainland

name
  • A historical region in British Columbia, British North America, British Empire 

  • The largest island in the Orkney Islands council area, to the north of Scotland. 

  • The largest island in the Shetland Islands council area, to the north of both Orkney and Scotland. 

How often have the words District and Mainland occurred in a corpus of books? (source: Google Ngram Viewer )