| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
| Suffolk | city | Montana | United States | 47.46694 | -109.355 | 3405 | 31 |
| Sula | city | Montana | United States | 45.83667 | -113.98083 | 4858 | 56 |
| Sullivan historical | city | Montana | United States | 48.9875 | -113.04861 | 4343 | 81 |
| Sumatra | city | Montana | United States | 46.61833 | -107.55056 | 3192 | 5 |
| Summit | city | Montana | United States | 48.31944 | -113.3525 | 5400 | 28 |
| Summit | city | Montana | United States | 45.21889 | -111.93 | 7345 | 20 |
| Summit Valley | city | Montana | United States | 45.77056 | -111.89167 | 4839 | 80 |
| Sumner | city | Montana | United States | 48.77972 | -108.10361 | 2942 | 15 |
| Sun Prairie | city | Montana | United States | 47.53694 | -111.48056 | 3398 | 364 |
| Sun Prairie | city | Montana | United States | 47.84556 | -107.74583 | 2395 | 5 |
| Sun River | city | Montana | United States | 47.53333 | -111.72056 | 3405 | 396 |
| Sunburst | city | Montana | United States | 48.88278 | -111.91056 | 3398 | 61 |
| Sundance | city | Montana | United States | 48.63389 | -112.53278 | 3976 | 61 |
| Sunlight | city | Montana | United States | 45.9 | -112.01667 | 4891 | 170 |
| Sunnyside | city | Montana | United States | 46.11556 | -112.99278 | 5987 | 4231 |
| Sunrise Trailer Court | city | Montana | United States | 48.16778 | -111.94056 | 3543 | 215 |
| Sunset | city | Montana | United States | 46.93806 | -113.46583 | 3687 | 103 |
| Sunset Trailer Court | city | Montana | United States | 46.23472 | -112.12361 | 4924 | 258 |
| Sunset Trailer Court | city | Montana | United States | 45.68694 | -111.04583 | 4816 | 26283 |
| Superior | city | Montana | United States | 47.19167 | -114.89083 | 2854 | 168 |
| Surprise Creek Colony | city | Montana | United States | 47.17028 | -110.33944 | 4399 | 42 |
| Sutherland historical | city | Montana | United States | 46.57806 | -105.34444 | 2358 | 23 |
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