Detroit is in the United States.
The Seventeenth United States Census , conducted by the Census Bureau , determined the resident population of the United States to be 150,697,361 , an increase of 14.5 percent over the 131,669,275 persons enumerated during the 1940 Census . Detroit . Since reaching a peak of 1.8 million at the 1950 census , Detroit 's population has declined by more than 60 per cent .