“An enumeration district, as used by the Bureau of the Census, was an area that could be covered by a single enumerator (census taker) in one census period. Enumeration districts varied in size from several city blocks in densely populated urban areas to an entire county in sparsely populated rural areas.
Enumeration district maps show the boundaries and the numbers of the census enumeration districts, which were established to help administer and control data collection. Wards, precincts, incorporated areas, urban unincorporated areas, townships, census supervisors` districts, and congressional districts may also appear on some maps. The content of enumeration district maps vary greatly. The base maps were obtained locally and include postal route maps, General Land Office maps, soil survey maps, and maps produced by city, county, and state government offices as well as commercial printers. Census officials then drew the enumeration district boundaries and numbers on these base maps.”