Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Abbott Ridge | Ridge | 1166 | Pondera | 48 24 09 N | 112 08 51 W |
| Abbott Spring | Spring | 1139 | Powder River | 45 26 16 N | 105 56 55 W |
| Abbotts Flats | Flat | 1180 | Flathead | 48 56 55 N | 114 24 60 W |
| ABC Little League Field | Park | 625 | Dawson | 47 06 48 N | 104 42 37 W |
| Abe (historical) | Populated Place | 1750 | Madison | 45 02 36 N | 111 41 03 W |
| Abe Lincoln Mountain | Summit | 1491 | Lincoln | 48 40 53 N | 115 53 53 W |
| Abe Lincone Mine | Mine | 1917 | Granite | 46 03 17 N | 113 31 13 W |
| Abe Post Office (historical) | Post Office | 1750 | Madison | 45 02 36 N | 111 41 03 W |
| Abe School (historical) | School | 1750 | Madison | 45 02 36 N | 111 41 03 W |
| Abel Park | Park | 1071 | Pondera | 48 10 34 N | 111 57 23 W |
| Abel Reservoir | Reservoir | 1073 | Carter | 45 43 31 N | 104 11 20 W |
| Abel School (historical) | School | 672 | Phillips | 48 20 27 N | 107 17 41 W |
| Abels Ranch | Locale | 678 | Phillips | 48 20 32 N | 107 17 11 W |
| Abenson Dam | Dam | 1880 | Beaverhead | 45 09 42 N | 112 29 09 W |
| Aber Hall | Building | 981 | Missoula | 46 51 44 N | 113 58 56 W |
| Aberdeen | Locale | 1196 | Big Horn | 45 03 16 N | 107 21 25 W |
| Aberdeen | Populated Place | 1196 | Big Horn | 45 03 16 N | 107 21 25 W |
| Aberdeen School (historical) | School | 1212 | Big Horn | 45 03 03 N | 107 21 12 W |
| Aberta Dam | Dam | 1010 | Garfield | 47 24 54 N | 107 25 02 W |
| Abey Reservoir | Reservoir | 781 | Valley | 48 33 22 N | 106 53 30 W |
| Abrahamson Coulee | Valley | | Phillips | 48 18 49 N | 107 34 29 W |
| Abrams Creek | Stream | | Beaverhead | 45 19 19 N | 113 10 50 W |
| Abrogast Spring | Spring | 1150 | Carter | 45 35 10 N | 104 05 53 W |
| Absaloka Baptist Church | Church | 926 | Big Horn | 45 36 06 N | 107 27 40 W |
| Absaloka Youth Camp | Locale | 1607 | Big Horn | 45 07 33 N | 107 53 55 W |
| Absaroka Fishing Access Site | Locale | 1236 | Stillwater | 45 31 39 N | 109 27 60 W |
| Absaroka Heights Baptist Church | Church | 1405 | Park | 45 39 40 N | 110 34 33 W |
| Absaroka Range | Range | 2524 | Park | 45 07 44 N | 110 07 05 W |
| Absaroka-Beartooth Wilderness | Reserve | 2606 | Park | 45 12 30 N | 110 17 33 W |
| Absaroka-Beartooth Wilderness Historical Marker | Park | 1504 | Park | 45 17 45 N | 110 50 05 W |
| Absarokee | Populated Place | 1231 | Stillwater | 45 31 14 N | 109 26 35 W |
| Absarokee Evangelical Church | Church | 1231 | Stillwater | 45 31 14 N | 109 26 35 W |
| Absarokee Fire Department | Building | 1231 | Stillwater | 45 31 14 N | 109 26 35 W |
| Absarokee Medical Clinic | Hospital | 1231 | Stillwater | 45 31 14 N | 109 26 35 W |
| Absarokee Post Office | Post Office | 1231 | Stillwater | 45 31 14 N | 109 26 35 W |
| Absarokee Public Schools | School | 1237 | Stillwater | 45 30 60 N | 109 26 41 W |
| Absher (historical) | Populated Place | 897 | Musselshell | 46 33 30 N | 107 59 02 W |
| Absher Post Office (historical) | Post Office | 897 | Musselshell | 46 33 30 N | 107 59 02 W |
| Absolen Reservoir | Reservoir | 828 | Rosebud | 46 32 10 N | 106 45 33 W |
| Abundant Life Christian Center | Church | 1071 | Pondera | 48 10 30 N | 111 56 47 W |
| Abundant Life Christian Fellowship | Church | 1022 | Cascade | 47 29 50 N | 111 17 25 W |
| Abundant Life Fellowship Church | Church | 1465 | Gallatin | 45 40 15 N | 111 09 08 W |
| Abundant Life Fellowship Church | Church | 1695 | Silver Bow | 46 00 12 N | 112 32 43 W |
| Access Reservoir | Reservoir | 712 | Valley | 47 59 27 N | 106 57 23 W |
| Accola | Populated Place | 1402 | Gallatin | 45 56 59 N | 111 11 07 W |
| Accola (historical) | Locale | 1402 | Gallatin | 45 56 59 N | 111 11 07 W |
| Accord (historical) | Locale | 632 | Valley | 48 09 56 N | 106 27 09 W |
| Accord School (historical) | School | 638 | Valley | 48 09 40 N | 106 25 35 W |
| Ace of Diamonds Dam | Dam | 1211 | Carter | 45 03 42 N | 104 59 08 W |
| Ace of Spades Dam | Dam | 659 | McCone | 47 54 24 N | 105 41 02 W |
| Aces Wild Dam | Dam | 1135 | Carter | 45 01 48 N | 104 50 32 W |
| Achegan Mine | Mine | 1416 | Granite | 46 29 43 N | 113 14 58 W |
| Ackerley School (historical) | School | 1055 | Fergus | 47 15 06 N | 109 42 55 W |
| Ackley Lake | Lake | 1316 | Judith Basin | 46 57 14 N | 109 56 20 W |
| Ackley Lake | Reservoir | 1315 | Judith Basin | 46 57 30 N | 109 55 57 W |
| Ackley Lake Campground | Locale | 1321 | Judith Basin | 46 56 50 N | 109 56 13 W |
| Ackley Lake Dam | Dam | 1315 | Judith Basin | 46 57 30 N | 109 55 57 W |
| Ackley Lake Feeder Canal | Canal | 1322 | Judith Basin | 46 58 05 N | 109 58 39 W |
| Ackley Lake Outlet Canal | Canal | 1302 | Judith Basin | 46 58 49 N | 109 57 28 W |
| Ackley Lake State Park | Park | 1321 | Judith Basin | 46 56 50 N | 109 56 13 W |
| Acme | Locale | 1101 | Teton | 47 52 38 N | 111 46 27 W |
| Acme Elevator | Locale | 1101 | Teton | 47 52 38 N | 111 46 27 W |
| Acorn Creek | Stream | | Rosebud | 46 46 54 N | 107 11 21 W |
| Acorn Flats | Flat | 1028 | Rosebud | 46 49 08 N | 107 02 12 W |
| Acorn Lake | Lake | 1826 | Sanders | 47 28 32 N | 115 08 53 W |
| Acorn Post Office (historical) | Post Office | 942 | Rosebud | 46 48 60 N | 107 16 29 W |
| Acorn Spring | Spring | 1060 | Garfield | 46 55 10 N | 107 05 30 W |
| Acres Gulch | Valley | | Lewis and Clark | 47 01 09 N | 112 00 01 W |
| Acton | Populated Place | 1159 | Yellowstone | 45 55 50 N | 108 40 51 W |
| Ada Creek | Stream | | Flathead | 48 17 23 N | 113 52 36 W |
| Ada Creek | Stream | | Garfield | 47 20 60 N | 106 33 26 W |
| Ada Mine | Mine | 1802 | Broadwater | 46 20 08 N | 111 40 31 W |
| Ada Post Office (historical) | Post Office | 987 | Blaine | 48 24 08 N | 109 25 56 W |
| Ada Post Office (historical) | Post Office | 779 | Rosebud | 46 17 39 N | 106 51 35 W |
| Ada Reservoir | Reservoir | 781 | Phillips | 48 53 14 N | 107 40 09 W |
| Ada Reservoir | Reservoir | 806 | Valley | 48 33 00 N | 106 52 24 W |
| Ada School (historical) | School | 981 | Blaine | 48 23 38 N | 109 26 31 W |
| Adair | Locale | 1047 | Flathead | 48 41 50 N | 114 11 33 W |
| Adair Creek | Stream | | Park | 45 45 48 N | 110 29 23 W |
| Adair Reservoir | Reservoir | 751 | Phillips | 48 38 21 N | 107 39 44 W |
| Adair Ridge | Ridge | 1626 | Flathead | 48 44 37 N | 114 03 43 W |
| Adams (historical) | Locale | 738 | Blaine | 48 35 45 N | 109 19 28 W |
| Adams Creek | Stream | | Carter | 45 32 32 N | 104 49 39 W |
| Adams Creek | Stream | | Meagher | 46 46 09 N | 110 48 60 W |
| Adams Creek | Stream | | Mineral | 47 01 49 N | 114 30 03 W |
| Adams Mountain | Summit | 1637 | Flathead | 48 30 26 N | 114 40 57 W |
| Adams Number 2 Dam | Dam | 957 | Fergus | 47 16 42 N | 108 41 15 W |
| Adams Number 3 Dam | Dam | 934 | Rosebud | 46 32 30 N | 106 30 26 W |
| Adams Number 4 Dam | Dam | 945 | Rosebud | 46 32 60 N | 106 30 20 W |
| Adams Number 5 Dam | Dam | 889 | Rosebud | 46 29 48 N | 106 30 50 W |
| Adams Reservoir | Reservoir | 1364 | Carbon | 45 04 18 N | 108 40 08 W |
| Adams Rocky Butte | Summit | 967 | Garfield | 47 13 11 N | 107 20 46 W |
| Adams School (historical) | School | 1044 | Treasure | 45 58 41 N | 107 13 40 W |
| Adaskavich Seventh Day Adventist School | School | 1005 | Toole | 48 30 19 N | 111 51 25 W |
| Addison School (historical) | School | 1142 | Fergus | 47 18 04 N | 109 37 03 W |
| Addition Creek | Stream | | Beaverhead | 45 43 47 N | 113 39 08 W |
| Addition Creek | Stream | | Flathead | 47 55 04 N | 113 31 19 W |
| Adel | Populated Place | 1510 | Cascade | 47 01 40 N | 111 37 26 W |
| Adel Mountain | Summit | 2164 | Cascade | 47 04 34 N | 111 42 24 W |
| Adel Post Office (historical) | Post Office | 1510 | Cascade | 47 01 40 N | 111 37 26 W |
| Adidias Dam | Dam | 819 | Garfield | 47 28 00 N | 106 47 44 W |
| Adkison Ranch | Locale | 1612 | Meagher | 46 16 24 N | 110 51 03 W |
| Adobe (historical) | Locale | 1691 | Madison | 45 19 05 N | 111 58 59 W |
| Adobe Creek | Stream | | Cascade | 47 31 25 N | 111 43 11 W |
| Adobe Ridge | Ridge | 1107 | Liberty | 48 38 27 N | 110 56 05 W |
| Adobetown Historical Marker | Park | 1684 | Madison | 45 19 05 N | 111 59 03 W |
| Adobetown Post Office (historical) | Post Office | 1691 | Madison | 45 19 05 N | 111 58 59 W |
| Adobetown School (historical) | School | 1691 | Madison | 45 19 05 N | 111 58 59 W |
| Adolph Creek | Stream | | Gallatin | 46 07 05 N | 111 07 29 W |
| Adson Creek | Stream | | Beaverhead | 45 44 15 N | 113 00 13 W |