Cities in State of Illinois, United States ( 474 )
- Smithton, Illinois
- South Barrington
- South Beloit
- South Chicago Heights
- South Elgin
- South Holland, Illinois
- South Jacksonville, Illinois
- Sparta, Illinois
- Spring Grove, Illinois
- Spring Valley, Illinois
- Springfield, Illinois
- Staunton, Illinois
- Steger, Illinois
- Sterling, Illinois
- Stickney, Illinois
- Stone Park
- Streamwood
- Streator
- Sugar Grove, Illinois
- Sullivan, Illinois
- Summit, Illinois
- Sumner, Illinois
- Swansea, Illinois
- Sycamore, Illinois
- Taylorville, Illinois
- Tilton, Illinois
- Tinley Park
- Tolono
- Trenton, Illinois
- Troy, Illinois
- Tuscola, Illinois
- University Park, Illinois
- Upper Alton
- Urbana, Illinois
- Vandalia, Illinois
- Venetian Village