Enumeration District (ED) Maps
An Enumeration District was an area that an enumerator (census taker) could completely cover within two weeks in cities and within four weeks in rural areas.
Enumeration District Maps show names of political jurisdictions (counties, cities, townships, and so forth), roads, waterways, and large properties, such as parks, cemeteries, prisons, golf courses, and so forth. In cities, maps may indicate boundaries of Wards and other subdivisions.
The Census Bureau annotated the maps with red, orange, yellow, and green pencil to show enumeration district and various political boundaries. Enumeration District numbers were usually written in orange pencil. Enumeration District numbers had two parts, such as 48-69, where 48 prefix was typically for the county and 69 suffix was for the specific area within the county. Independent cities and very large cities (such as Chicago) had their own prefixes instead of using the county prefix. Thus, although Chicago is within the boundaries of Cook County, enumeration districts in Chicago had a prefix was 103 instead Cook County’s prefix of 16.
The image below is a detail from a larger map. It shows a portion of Washington and Sylvania Townships in Lucas County, Ohio (National Archives Identifier 26421336). At the top is the boundary between the states of Michigan and Ohio. There is a neighborhood called Trilby, numerous named streets, a golf course, and three named ditches (waterways). The boundary line between Sylvania and Washington Townships is red. Enumeration district boundaries are marked with red, orange, or yellow lines.
Enumeration district maps for the 1950 census are available on this website as well as in the National Archives Catalog.