Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Ash Coulee | Valley | | Valley | 48 22 12 N | 106 58 25 W |
| Ash Coulee | Valley | | Valley | 48 35 26 N | 106 55 53 W |
| Ash Coulee School (historical) | School | 980 | Fallon | 46 37 38 N | 104 16 12 W |
| Ash Coulee School (historical) | School | 821 | Treasure | 46 12 39 N | 107 26 40 W |
| Ash Creek | Stream | | Big Horn | 45 32 19 N | 106 58 13 W |
| Ash Creek | Stream | | Big Horn | 45 43 16 N | 107 17 32 W |
| Ash Creek | Stream | | Custer | 46 06 08 N | 105 08 02 W |
| Ash Creek | Stream | | Custer | 46 07 27 N | 105 49 27 W |
| Ash Creek | Stream | | Custer | 46 25 38 N | 105 32 17 W |
| Ash Creek | Stream | | Custer | 46 33 20 N | 104 51 38 W |
| Ash Creek | Stream | | Fallon | 46 11 04 N | 104 44 14 W |
| Ash Creek | Stream | | Garfield | 46 57 23 N | 106 07 49 W |
| Ash Creek | Stream | | Garfield | 47 37 49 N | 106 18 49 W |
| Ash Creek | Stream | | McCone | 47 18 30 N | 105 45 03 W |
| Ash Creek | Stream | | Powder River | 45 33 57 N | 105 29 56 W |
| Ash Creek | Stream | | Powder River | 45 44 21 N | 106 05 06 W |
| Ash Creek | Stream | | Powder River | 45 21 47 N | 106 08 36 W |
| Ash Creek | Stream | | Prairie | 46 48 32 N | 104 54 32 W |
| Ash Creek | Stream | | Prairie | 46 48 09 N | 105 15 58 W |
| Ash Creek | Stream | | Prairie | 46 46 28 N | 104 47 04 W |
| Ash Creek | Stream | | Rosebud | 45 40 18 N | 106 28 52 W |
| Ash Creek | Stream | | Wibaux | 46 38 40 N | 104 12 43 W |
| Ash Creek Dam | Dam | 855 | Prairie | 46 59 12 N | 106 00 50 W |
| Ash Creek Reservoir | Reservoir | 1171 | Powder River | 45 20 41 N | 106 02 21 W |
| Ash Creek Reservoir Number Two | Reservoir | 1062 | Powder River | 45 21 09 N | 106 05 08 W |
| Ash Creek School (historical) | School | 972 | Custer | 45 57 56 N | 105 44 44 W |
| Ash Creek School (historical) | School | 826 | Prairie | 46 45 28 N | 104 38 40 W |
| Ash Creek School (historical) | School | 862 | Rosebud | 46 09 04 N | 106 15 30 W |
| Ash Draw | Valley | | Carter | 45 11 34 N | 105 00 11 W |
| Ash Grove School (historical) | School | 840 | Rosebud | 46 12 50 N | 106 56 42 W |
| Ash Mountain | Summit | 3116 | Park | 45 05 60 N | 110 32 58 W |
| Ash Mountain Trail | Trail | 2887 | Park | 45 05 33 N | 110 31 01 W |
| Ash Number 1 Dam | Dam | 893 | Custer | 45 58 12 N | 105 09 26 W |
| Ashbaugh Creek | Stream | | Beaverhead | 45 03 11 N | 112 48 41 W |
| Ashbaughs Saloon (historical) | Locale | 1684 | Beaverhead | 45 05 38 N | 112 40 15 W |
| Ashbough Canyon | Valley | | Beaverhead | 44 46 33 N | 112 42 53 W |
| Ashbough Canyon | Valley | | Beaverhead | 45 02 13 N | 112 32 46 W |
| Ashbough Spring | Spring | 2244 | Beaverhead | 44 49 58 N | 112 39 19 W |
| Ashbridge Spring | Spring | 1671 | Fergus | 46 46 20 N | 109 06 57 W |
| Ashby Creek | Stream | | Missoula | 46 49 31 N | 113 35 52 W |
| Ashby Creek | Stream | | Missoula | 46 52 57 N | 113 35 22 W |
| Ashdale Post Office (historical) | Post Office | 835 | Sheridan | 48 42 38 N | 104 58 10 W |
| Ashenhurst Number 1 Dam | Dam | 934 | Rosebud | 46 01 42 N | 106 50 32 W |
| Ashenhurst Number 2 Dam | Dam | 940 | Rosebud | 45 59 42 N | 106 52 02 W |
| Ashfield | Populated Place | 681 | Phillips | 48 27 43 N | 107 28 26 W |
| Ashfield (historical) | Locale | 681 | Phillips | 48 27 43 N | 107 28 26 W |
| Ashfield Post Office (historical) | Post Office | 681 | Phillips | 48 27 43 N | 107 28 26 W |
| Ashfield Reservoir | Reservoir | 711 | Phillips | 48 25 54 N | 107 29 03 W |
| Ashford Coulee | Valley | | Phillips | 48 21 01 N | 107 13 48 W |
| Ashford Spring | Spring | 1658 | Meagher | 46 48 27 N | 111 22 54 W |
| Ashford Spring | Spring | 769 | Valley | 48 21 01 N | 107 11 20 W |
| Ashford Tank | Reservoir | 1762 | Meagher | 46 46 31 N | 111 21 30 W |
| Ashland | Populated Place | 890 | Rosebud | 45 35 40 N | 106 16 15 W |
| Ashland Christian Fellowship | Church | 890 | Rosebud | 45 35 40 N | 106 16 15 W |
| Ashland Community Church | Church | 890 | Rosebud | 45 35 40 N | 106 16 15 W |
| Ashland Fort Howes Ranger Station | Locale | 904 | Rosebud | 45 35 33 N | 106 16 25 W |
| Ashland Post Office | Post Office | 890 | Rosebud | 45 35 40 N | 106 16 15 W |
| Ashland School | School | 890 | Rosebud | 45 35 42 N | 106 16 17 W |
| Ashley (historical) | Populated Place | 898 | Flathead | 48 11 30 N | 114 19 58 W |
| Ashley Coulee | Valley | | Golden Valley | 46 36 41 N | 109 13 47 W |
| Ashley Creek | Stream | | Flathead | 48 09 32 N | 114 12 45 W |
| Ashley Creek | Stream | | Lake | 47 38 13 N | 114 02 40 W |
| Ashley Creek | Stream | | Lake | 47 23 42 N | 114 05 47 W |
| Ashley Creek | Stream | | Sanders | 47 34 49 N | 115 17 06 W |
| Ashley Creek Bridge | Bridge | 885 | Flathead | 48 08 07 N | 114 14 41 W |
| Ashley Creek Ditch | Canal | 943 | Flathead | 48 13 17 N | 114 24 17 W |
| Ashley Creek Fishing Access Site | Locale | 978 | Flathead | 48 05 47 N | 114 33 08 W |
| Ashley Creek School (historical) | School | 1013 | Flathead | 48 06 08 N | 114 34 19 W |
| Ashley Dam | Dam | 1204 | Flathead | 48 10 60 N | 114 37 21 W |
| Ashley Divide | Ridge | 1816 | Flathead | 48 17 26 N | 114 42 38 W |
| Ashley Divide Trail | Trail | 1847 | Flathead | 48 16 31 N | 114 42 20 W |
| Ashley Lake | Lake | 1204 | Flathead | 48 12 16 N | 114 36 59 W |
| Ashley Lake | Reservoir | 1204 | Flathead | 48 10 60 N | 114 37 21 W |
| Ashley Lake Campground | Locale | 1210 | Flathead | 48 12 42 N | 114 34 10 W |
| Ashley Lake Campground | Locale | 1205 | Flathead | 48 12 49 N | 114 37 01 W |
| Ashley Lake Fishing Access Site | Locale | 1207 | Flathead | 48 12 49 N | 114 37 02 W |
| Ashley Lakes | Lake | 1632 | Lake | 47 22 38 N | 113 57 48 W |
| Ashley Mountain | Summit | 1918 | Flathead | 48 16 53 N | 114 42 44 W |
| Ashley Mountain Lookout Tower | Tower | 1918 | Flathead | 48 16 52 N | 114 42 43 W |
| Ashley Post Office (historical) | Post Office | 898 | Flathead | 48 11 30 N | 114 19 58 W |
| Ashley Post Office (historical) | Post Office | 880 | Petroleum | 47 09 02 N | 108 09 16 W |
| Ashley School (historical) | School | 877 | Petroleum | 47 09 10 N | 108 09 34 W |
| Ashleys Settlement (historical) | Populated Place | 740 | Sanders | 47 34 35 N | 115 14 49 W |
| Ashmoor (historical) | Populated Place | 1016 | Chouteau | 48 03 48 N | 111 19 33 W |
| Ashmoor Post Office (historical) | Post Office | 1016 | Chouteau | 48 03 48 N | 111 19 33 W |
| Ashmoor School (historical) | School | 1016 | Chouteau | 48 03 48 N | 111 19 33 W |
| Ashmore (historical) | Locale | 812 | Mineral | 47 14 18 N | 114 59 58 W |
| Ashmore School (historical) | School | 812 | Mineral | 47 14 18 N | 114 59 58 W |
| Ashuelot | Populated Place | 1135 | Cascade | 47 33 26 N | 111 48 41 W |
| Ashuelot Bench | Bench | 1139 | Cascade | 47 33 25 N | 111 49 11 W |
| Askin Dam | Dam | 867 | Fallon | 46 20 00 N | 104 44 38 W |
| Asp Gulch | Valley | | Sweet Grass | 45 37 46 N | 109 58 08 W |
| Aspen Campground | Locale | 1982 | Beaverhead | 45 25 15 N | 112 51 16 W |
| Aspen Campground | Locale | 1564 | Cascade | 46 59 35 N | 110 46 06 W |
| Aspen Campground | Locale | 1642 | Sweet Grass | 45 27 25 N | 110 11 50 W |
| Aspen Creek | Stream | | Madison | 45 20 51 N | 111 31 54 W |
| Aspen Grove Cabin | Locale | 2124 | Big Horn | 45 05 09 N | 107 50 58 W |
| Aspen Grove Campground | Locale | 1456 | Lewis and Clark | 46 58 43 N | 112 31 53 W |
| Aspen Mine | Mine | 2523 | Beaverhead | 45 29 18 N | 113 03 13 W |
| Aspen Spring | Spring | 2373 | Beaverhead | 44 45 01 N | 112 54 00 W |
| Aspen Spring | Spring | 1131 | Carter | 45 54 03 N | 104 27 28 W |
| Aspenwood Camp | Locale | 1470 | Glacier | 48 32 40 N | 113 12 43 W |
| Assembly of God Calvary Temple | Church | 814 | Wibaux | 46 59 16 N | 104 11 37 W |
| Assembly of God Church | Church | 1039 | Blaine | 48 02 05 N | 108 31 60 W |
| Assembly of God Church | Church | 721 | Blaine | 48 31 60 N | 108 47 03 W |
| Assembly of God Church | Church | 739 | Blaine | 48 35 31 N | 109 13 57 W |
| Assembly of God Church | Church | 743 | Custer | 46 23 06 N | 105 48 54 W |
| Assembly of God Church | Church | 761 | Daniels | 48 47 18 N | 105 25 11 W |
| Assembly of God Church | Church | 628 | Dawson | 47 05 37 N | 104 42 50 W |
| Assembly of God Church | Church | 1608 | Deer Lodge | 46 07 38 N | 112 57 01 W |