Territorial, state, and federal censuses have been indexed in one alphabetical sequence along with county election returns and other records. Records for the 1825, 1835, and 1845 state censuses of many counties are missing or incomplete. The Illinois State Archives has the original card index complete through 1855. A microfilm copy made before the index was completed is:

Name Index to Early Illinois Records (Springfield, Ill.: Illinois State Archives, 1975). On 248 FHL films 1001592 (first of 248 films). At the time the index was microfilmed, most of the indexing of the 1855 census had not been completed.

Existing and lost censuses

Why use a census?

A well-indexed census is one of the easiest ways to locate where an ancestor's family lived and when they lived there. You can also use censusesof State, 1855 state census of Illinois (Salt Lake City, Utah : Filmed by the Genealogical Society of Utah, 1975; microreproduction of original records at the Illinois State Archives, Springfield, Illinois]][FHL Film 976178 item 11+].

↑ Illinois, Secretary of State, 1840 state census (Salt Lake City, Utah : Filmed by the Genealogical Society of Utah, 1976;Microfilm of original record in Springfield, Ill., Illinois State Archives)[FHL Film 1004694-95].