Towns
| State | City/Town | Town Title |
|---|---|---|
| Illinois | Saint Francisville | Saint Francisville, IL |
| Illinois | Saint Jacob | Saint Jacob, IL |
| Illinois | Saint Joseph | Saint Joseph, IL |
| Illinois | Saint Libory | Saint Libory, IL |
| Illinois | Saint Peter | Saint Peter, IL |
| Illinois | Sainte Marie | Sainte Marie, IL |
| Illinois | Salem | Salem, IL |
| Illinois | San Jose | San Jose, IL |
| Illinois | Sandoval | Sandoval, IL |
| Illinois | Sandwich | Sandwich, IL |
| Illinois | Saunemin | Saunemin, IL |
| Illinois | Savanna | Savanna, IL |
| Illinois | Savoy | Savoy, IL |
| Illinois | Sawyerville | Sawyerville, IL |
| Illinois | Saybrook | Saybrook, IL |
| Illinois | Scales Mound | Scales Mound, IL |
| Illinois | Schaumburg | Schaumburg, IL |
| Illinois | Scheller | Scheller, IL |
| Illinois | Schiller Park | Schiller Park, IL |
| Illinois | Sciota | Sciota, IL |
| Illinois | Scott Air Force Base | Scott Air Force Base, IL |
| Illinois | Scottville | Scottville, IL |
| Illinois | Seaton | Seaton, IL |
| Illinois | Seatonville | Seatonville, IL |
| Illinois | Secor | Secor, IL |