St. Clair County (other)
St. Clair County is the name of four counties in the United States: * St. Clair County, Alabama * St. Clair County, Illinois * St. Clair County, Michigan * St. Clair County, Missouri St. Clair County is a county located in the western portion of the U.S. state of Missouri. As of the 2020 census, the population was 9,284. Its county seat is Osceola. The largest city is Appleton City. The county was organized in 1841 and n ...