Places beginning with SU in Illinois, United States
- Sublette
- Sublette, Township of
- Sudduth (historical)
- Suez, Township of
- Sugar Creek Ranch
- Sugar Creek, Township of
- Sugar Grove
- Sugar Grove
- Sugar Grove
- Sugar Grove Number 5 Election Precinct
- Sugar Grove, Township of
- Sugar Island
- Sugarloaf Heights
- Sugar Loaf, Township of
- Sullivan
- Sullivan Center (historical)
- Sullivan, Township of
- Sullivan, Township of
- Sullivant, Township of
- Sulphur Springs
- Sulphur Springs (historical)
- Summerdale (subdivision)
- Summerfield
- Summer Hill
- Summersville
- Summerville
- Summit
- Summit
- Summit, Township of
- Summum
- Sumner
- Sumner, Township of
- Sumner, Township of
- Sumpter, Township of
- Sunbeam
- Sunbury
- Sunbury, Township of
- Sunfield
- Sunfield Election Precinct
- Sunnybrook Meadows
- Sunny Crest
- Sunny Hill
- Sunny Hill
- Sunny Hill Estates
- Sunnyland
- Sunnyside
- Sunnyside
- Sunnyside
- Sunnyside (subdivision)
- Sunrise Hills
- Sunrise Ridge
- Sun River Terrace
- Sunset Harbor
- Sunset Villa
- Surrey
- Surrey Woods (subdivision)
- Sutter
- Sutter
- Sutton