| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Soda Springs | city | Montana | United States | 45.57 | -108.27 | 4189 | |
| Sodak Mill | city | Montana | United States | 45.43 | -112.60 | 5052 | |
| Sohon | city | Montana | United States | 47.44 | -115.70 | 4399 | |
| Sollid (historical) | city | Montana | United States | 48.18 | -111.50 | 3392 | |
| Somers | city | Montana | United States | 48.08 | -114.22 | 2893 | |
| Sonnette | city | Montana | United States | 45.41 | -105.83 | 4189 | |
| Soudan | city | Montana | United States | 47.03 | -114.40 | 3349 | |
| Sour Dough Flat (historical) | city | Montana | United States | 48.00 | -109.38 | 3746 | |
| Sourdough | city | Montana | United States | 45.90 | -109.81 | 4609 | |
| South Browning | city | Montana | United States | 48.55 | -113.01 | 4399 | |
| South Fork (historical) | city | Montana | United States | 48.35 | -114.01 | 4189 | |
| South Glastonbury | city | Montana | United States | 45.33 | -110.81 | 5029 | |
| Southern Cross (historical) | city | Montana | United States | 46.21 | -113.24 | 7549 |