| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Black Eagle | city | Montana | United States | 47.52 | -111.28 | 3398 | |
| Blackfoot | city | Montana | United States | 48.58 | -112.88 | 4199 | |
| Blackfoot (historical) | city | Montana | United States | 47.45 | -107.43 | 3349 | |
| Blackfoot City (historical) | city | Montana | United States | 46.68 | -112.54 | 5928 | |
| Blackleaf | city | Montana | United States | 48.01 | -112.61 | 5029 | |
| Blacktail | city | Montana | United States | 48.28 | -113.45 | 4399 | |
| Blackwood | city | Montana | United States | 45.64 | -111.15 | 5029 | |
| Blair | city | Montana | United States | 48.15 | -104.63 | 1919 | |
| Blair Crossing | city | Montana | United States | 48.40 | -112.29 | 3615 | |
| Blakeslee (historical) | city | Montana | United States | 47.19 | -108.67 | 3349 | |
| Blanchards Corner | city | Montana | United States | 47.56 | -114.87 | 3349 | |
| Blatchford | city | Montana | United States | 46.71 | -105.45 | 2509 | |
| Blazing Place | city | Montana | United States | 46.22 | -111.97 | 5400 | |
| Bloomfield | city | Montana | United States | 47.41 | -104.92 | 2637 | |
| Blossburg | city | Montana | United States | 46.63 | -112.32 | 5869 | |
| Blue Cloud (historical) | city | Montana | United States | 46.59 | -112.16 | 4438 | |
| Blue Mountain Trailer Park | city | Montana | United States | 46.81 | -114.09 | 3349 | |
| Bluffport | city | Montana | United States | 46.81 | -105.17 | 2509 | |
| Blythe | city | Montana | United States | 47.30 | -110.83 | 4189 |