The 1930 census data is a great place to start. It was taken beginning on April 2, 1930, except for the Alaska census, which began early, on October 1, 1929. Fifty-six states and territories were enumerated and marked according to counties within those states and territories. Each county was given a number according to alphabetical order and then given more specific identification numbers within that county. For example, a county might be marked 1-1 or 10-73. The Virgin Islands, Guam, American Samoa and the Canal Zone were not subjected to this system of numbering.
Like the censuses that came before it, the 1930 census covered names, ages, races, relationships, house numbers and streets of residence. It also included information on home ownership or rental, literacy and schooling, employment information, citizenship and immigration information and birthplaces of residents and their parents.