US Federal Census Dates

Importance of Official Census Dates

It is important to use the official census dates when incorporating census information into genealogy records. Each census year is assigned an official date by the census agency. Enumerators are instructed to ask that answers to their questions be "as of" that official date, notwithstanding the actual date a particular enumerator may have visited a particular household, and whether or not that date was recorded on the schedule. Because it is impossible to know if enumerators and attestors adhered to those "as of" instructions, assuming the official date was adhered to assures consistency in genealogy records when calculating event dates from census information.  This is especially important in later censuses, where the age of children may be given in both years and months.

Official Census Dates

1790-1820: First Monday in August

1790: 2 August

1800: 4 August

1810: 6 August

1820: 7 August

1830-1880: June 1 for all years

1890: First Monday in June -- falling on June 2

1900: June 1

1910: April 15

1920: January 1

1930: April 1

1940: April 1

Source: U.S. National Archives