St. Charles County, Missouri Genealogy
The St. Charles County Historical Society has an extensive collection of materials relevant to family history. They are the repository of 19th century will books, probate records, naturalization records, and court records. They also have many compiled genealogies, and indexes to many church records and cemeteries of the county. See their website, www.scchs.org, for contact information. The society does research for a fee.
State census was taken in 1852, 1868, and 1876. The 1852 census lists head of household, the 1868 and 1876 include every person in household.