The actual date of the enumeration appears on the heading of each page of the census schedule, but all responses were to reflect the individual's status as of 1 January, even if the status had changed between 1 January and the day of enumeration.

According to the Census Bureau, "Beginning in 1910, the minimum population threshold to be categorized as an urban place was set at 2,500.

"Urban" was defined as including all territory, persons, and housing units within an incorporated area that met the population threshold.

Several organizations also host images of the microfilmed census online, and digital indices.

Aggregate data for small areas, together with electronic boundary files, can be downloaded from the National Historical Geographic Information System.