The US Government is due to release the 1940 Census On 2 April 2012. The United States had a population of about 132 million in 1940; they had endured the Great Depression and were on the verge of entering World War 2. Census enumerators went door-to-door asking where residents lived in 1935 because so many people moved between 1930 and 1940. They also asked how many weeks the head of the household was employed during the previous year because of widespread unemployment.
The 1940 census will be the first one released digitally. However, the 3.8 million raw images of census forms won’t be indexed, so researchers will have to look up geographic areas and search addresses, rather than searching by keywords. Ancestry and Heritage Quest have said they plan to index the census by the end of the year.