- Chatton
- Chatton Island
- Cheshire Hills
- Chestline
- Country Meadows
- Cairo Junction
- Clank
- Commerce Towhead (historical)
- Candlewick Lake
- Cooperstown
- Center Hill
- Churchill
- Clarion
- Coal Hollow
- Cabery
- Cahokia
- Calumet City
- Calumet Park
- Camp Point
- Campbells Island
- Carroll Island
- Carroll Island
- Centerville
- Clarksville Island
- Cliffdale
- Conrad
- Coon Island
- Campbell Hill
- Campus
- Cantrall