EDs, strictly defined, were not used until the 1880 census. The early censuses used the term subdivision to refer to part of a supervisor's or marshal's division or district. Subdivisions in the early censuses comprised towns, townships, or other units comparable to MCDs (municipal civil divisions).

Most early ED descriptions are general and largely served as documentation of the names of enumerators and rates of pay. They may simply state that a census taker had to enumerate an entire county or an unspecified part of a subdivision. Beginning with 1850, the ED descriptions become increasingly detailed.

To use ED descriptions, a researcher should try to determine the location of a family, person, or institution in a specific census year. In the late 1800s, death and birth certificates, city directories, tax records, or other sources may provide this information.

At a minimum, the researcher must determine the state or territory and try to identify the county. Descriptions found in these microfilms may help narrow the search for the specific microfilm roll and for the census schedules contained within a roll, by specifying in what county a locality (including MCDs, neighborhoods, or post offices) was during a specific census year.

The 1880-1890 descriptions are the most detailed often noting street names or ranges and specifying the corresponding EDs. U.S. Ward Maps are indispensable aids that work hand in hand with this information to help researchers find the correct microfilm roll and the location of a specific Enumeration District.

The same research steps can help researchers find the 1890-1920 schedules.

Note: An EDs location and number often changed for each census year. So, it is important to find the ED's location each time and not just assume that it has remained the same.