| Silverton, OR (City) |
| Silverton, MN (Township) |
| Silvesta, ND (Township) |
| Silvis, IL (City) |
| Simi Valley, CA (City) |
| Simla, CO (Town) |
| Simmesport, LA (Town) |
| Simonton, TX (City) |
| Simpson, KS (City) |
| Simpson, LA (Village) |
| Simpson, IL (Village) |
| Simpson, NC (Village) |
| Simpson County, KY (County) |
| Simpson County, MS (County) |
| Simpsonville, SC (City) |
