Eighty years ago, the census of 1940—the 16th in the nation’s history—was carried out beginning in April. The 1940 census forms a critical link to our shared past and provides a window into an American world only one year away from being engulfed by war. It would also hold both immediate and long-lasting ramifications for the country and its citizens, some of which have only recently begun to come to light.
https://www.nationalww2museum.org/war/articles/1940-united-states-census