United States Census Enumerators were instructed to take down the names of the family they were visiting, as the family was composed on the OFFICIAL DATE of the census — not the day of the actual visit.

The OFFICIAL DATES of the various censuses were:

  • –First Monday in August for 1790-1820 Schedules.
  • –June 1st for 1830-1880 Censuses.
  • –First Monday in June for 1890 (Most of This Census Was Destroyed by Fire in 1921).
  • –June 1st for 1900.
  • –April 15th for 1910.
  • –January 1st for 1920.
  • –April 1st for 1930.

For more information on using census records for genealogical research, see:
“U.S. Census Records: Soundexes, Indexes and Finding Aids”