US Census Enumeration Maps 1900–1940

Hampton County SC 1940 Enumeration District Map - FamiySearch
National Archives & Records Administration

Maps are an invaluable resource for genealogists—useful for establishing where your ancestor lived, who their neighbors were, and where the closest courthouse, schools and churches were located. For those of you researching ancestors who appeared in the U.S. Census between 1900 and 1940, this free collection of U.S. Enumeration District Maps for the Twelfth through the Sixteenth Censuses, 1910–1940 is well worth checking out.

Beginning with the 1880 Census, the U.S. Census Bureau divided the nation into enumeration districts, each representing an area that could be covered by a single census enumerator in one census period (about two to four weeks for the 1930 census). An enumeration district map was prepared for each enumerator, with an additional copy kept by the office. These office copies are now in the custody of the National Archives and Records Administration (NARA), and were microfilmed by the Bureau of the Census in the 1950s. The 73 rolls of NARA microfilm (NARA microfilm publication A3378) are what was digitized and placed online by FamilySearch.

Most of the maps are arranged alphabetically by state, then county, and then census year, followed by local jurisdiction (except in very rural counties). There are a few exceptions to this arrangement, such as Cook County, Illinois, where maps are arranged first by town, and then by census year.

It is also important to note that while almost all counties are included in this collection, maps may not be available for every census year for a given county. In South Carolina, for example, enumeration maps for the 1930 and 1940 census are all that is available for many counties.