The National Archives and Record Administration released for the first time yesterday the largest collection of digital information from the 1940 Census.
The treasure trove of data provides a snapshot of life during the Great Depression.
During the 1930s, the Dust Bowl pushed many poverty-stricken Americans west in search of work and more productive farmlands.
Population declined by more than 25 percent in some rural counties of Oklahoma, Texas and Kansas. Clark County, Nevada, for example, nearly doubled in population to 16,000 people.
California on the hand, grew substantially between 1930 and 1940. Los Angeles county gained more than half a million people — the largest increase in population of any county in that decade.