St. Clair County, IL Population St. Clair County, IL Population by Year St. Clair County, IL Population by Gender St. Clair County, IL Population by Age St. Clair County, IL Population by Race & Ethnicity Belleville, IL Population O'Fallon, IL Population Collinsville, IL Population East St. Louis, IL Population Fairview Heights, IL Population Shiloh, IL Population Swansea, IL Population Cahokia, IL Population Columbia, IL Population Mascoutah, IL Population

Alorton Belleville Brooklyn Cahokia Caseyville Centreville Collinsville Columbia Dupo East Carondelet East St. Louis Fairmont City Fairview Heights Fayetteville Freeburg Hecker Lebanon Lenzburg Madison Marissa Mascoutah Millstadt New Athens New Baden O'Fallon Sauget Shiloh Smithton St. Libory Summerfield Swansea Washington Park