- Kenilworth
- Kingston
- Kirkland
- Kirkwood
- Knoxville
- Kane
- Kansas
- Kell
- Kilbourne
- Kincaid
- Kinderhook
- Kahm
- Kampenville
- Kamps-Stiens Island
- Kaneland Estates
- Kaneville
- Kaolin
- Karbers Ridge
- Kasbeer
- Kaser
- Kaskaskia Island
- Katy Did
- Kaufman
- Kay - Lou Trailer Courts
- Kay Island
- Kedron
- Keenesville
- Keeneyville
- Kegley
- Keller