Found at Rootsweb: http://www.rootsweb.com/~rwguide/lesson9.htm Official census dates were: First Monday in August for 1790-1820 schedules June 1 for 1830-1880 First Monday in June for 1890 (most of this schedule was destroyed or badly damaged by a fire in 1921 - a card index to the 6,160 names on the surviving schedules is available on two rolls of National Archives film No. M496) June 1 for 1900 April 15 for 1910 January 1 for 1920 Suggested Reading & References Bohme, Frederick G., 200 Years of U.S. Census Taking: Population and Housing Questions, 1790-1990. Washington, DC: U.S. Government Printing Office, 1989. Dollarhide, William. The Census Book: A Genealogist's Guide to Federal Census Facts, Schedules and Indexes. Bountiful, Utah.: Heritage Quest, 1999. Szucs, Loretto Dennis and Sandra Hargreaves Luebking. The Source: A Guidebook of American Genealogy. Revised Edition. Salt Lake City, Utah: Ancestry, Inc., 1997. Thorndale, William and William Dollarhide. Map Guide to the U.S. Federal Censuses, 1790-1920. Baltimore, Md.: Genealogical Publishing Co., Inc., 1987.