| Sioux Township, IA (Township) |
| Sioux Township, IA (Township) |
| Sioux Trail, ND (Township) |
| Sioux Valley, MN (Township) |
| Sioux Valley, SD (Township) |
| Sipsey, AL (Town) |
| Siren Town, WI (Town) |
| Siren Village, WI (Village) |
| Siskiyou County, CA (County) |
| Sisseton, SD (Township) |
| Sisseton, SD (City) |
| Sisseton, SD (Township) |
| Sister Bay Village, WI (Village) |
| Sisters, OR (City) |
| Sistersville, WV (City) |
