Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| South Meadow Creek | Stream | | Madison | 45 26 31 N | 111 42 44 W |
| South Meadow Creek Dam | Dam | 2636 | Madison | 45 27 18 N | 111 55 15 W |
| South Meadow Creek Lake | Lake | 2640 | Madison | 45 27 25 N | 111 55 39 W |
| South Meadow Creek Ranger Station | Locale | 1991 | Madison | 45 27 27 N | 111 51 34 W |
| South Meadow Lake | Reservoir | 2636 | Madison | 45 27 18 N | 111 55 15 W |
| South Miller Creek | Stream | | Custer | 46 01 39 N | 106 06 06 W |
| South Moccasin Mountains | Range | 1515 | Fergus | 47 10 21 N | 109 31 26 W |
| South Nashua School (historical) | School | 645 | Valley | 48 05 18 N | 106 19 44 W |
| South Oak Mine | Mine | 1977 | Beaverhead | 45 09 60 N | 112 57 03 W |
| South One Horse Lake | Lake | 2266 | Missoula | 46 39 49 N | 114 14 24 W |
| South Pacific | Mine | 1913 | Lewis and Clark | 46 28 20 N | 112 14 25 W |
| South Park | Park | 1512 | Gallatin | 45 39 15 N | 111 02 23 W |
| South Park | Park | 986 | Rosebud | 45 52 48 N | 106 37 22 W |
| South Park | Park | 951 | Yellowstone | 45 46 25 N | 108 29 58 W |
| South Pass Creek Spring | Spring | 1999 | Sweet Grass | 45 28 19 N | 109 56 32 W |
| South Peak | Summit | 2155 | Cascade | 47 22 21 N | 110 38 23 W |
| South Picket Pin Lake | Lake | 2773 | Sweet Grass | 45 25 31 N | 110 02 44 W |
| South Pine Oil Field | Oilfield | 797 | Wibaux | 46 44 29 N | 104 33 42 W |
| South Pole Creek | Stream | | Broadwater | 46 26 35 N | 111 42 50 W |
| South Pondera Coulee | Valley | | Pondera | 48 08 14 N | 111 38 12 W |
| South Prong Black Coulee | Valley | | Rosebud | 46 24 51 N | 106 39 43 W |
| South Rigby Dam | Dam | 1032 | Pondera | 48 06 06 N | 111 46 27 W |
| South Riverside Cabin | Locale | 2307 | Gallatin | 44 31 38 N | 111 05 28 W |
| South Robinson Spring | Spring | 1803 | Stillwater | 45 28 21 N | 109 50 27 W |
| South Rock Creek Reservoir Dam | Dam | 739 | McCone | 47 42 00 N | 106 06 44 W |
| South Route of Old Nez Perce Trail | Trail | 2176 | Ravalli | 45 42 47 N | 114 26 37 W |
| South Sand Creek | Stream | | Big Horn | 45 23 09 N | 107 27 01 W |
| South Sandstone Creek Dam | Dam | 881 | Fallon | 46 20 00 N | 104 29 02 W |
| South Sandstone Fishing Access Site | Locale | 870 | Fallon | 46 19 57 N | 104 28 27 W |
| South Sandstone Reservoir | Reservoir | 870 | Fallon | 46 20 20 N | 104 28 41 W |
| South Sawmill Creek | Stream | | Garfield | 47 32 12 N | 107 26 10 W |
| South School (historical) | School | 1051 | Fergus | 47 34 10 N | 109 43 49 W |
| South School (historical) | School | 761 | Phillips | 48 16 40 N | 108 15 32 W |
| South School (historical) | School | 663 | Roosevelt | 48 10 10 N | 105 29 30 W |
| South Section 6 Mine | Mine | 2791 | Madison | 45 36 05 N | 112 01 10 W |
| South Shed Coulee | Valley | | Valley | 48 12 38 N | 107 15 27 W |
| South Shore Trail | Trail | 1600 | Glacier | 48 28 18 N | 113 22 49 W |
| South Shotgun Coulee | Valley | | Phillips | 47 50 56 N | 107 27 02 W |
| South Side Canal | Canal | 1577 | Meagher | 46 32 28 N | 110 52 20 W |
| South Side Public School (historical) | School | 1702 | Carbon | 45 10 60 N | 109 14 60 W |
| South Side Reservoir | Reservoir | 1905 | Silver Bow | 45 08 13 N | 112 31 59 W |
| South Side School | School | 636 | Valley | 48 11 31 N | 106 38 23 W |
| South Spring Creek | Stream | | Carter | 45 50 11 N | 104 55 13 W |
| South Stacey School | School | 1035 | Powder River | 45 41 56 N | 105 53 19 W |
| South Stacey Spring | Spring | 1114 | Powder River | 45 41 58 N | 105 57 01 W |
| South Sunday Creek | Stream | | Custer | 46 26 56 N | 105 53 48 W |
| South Swamp Creek | Stream | | Ravalli | 46 30 02 N | 114 06 09 W |
| South Twitchell Point | Cape | 716 | McCone | 47 33 34 N | 106 13 19 W |
| South Valley Church | Church | 823 | Dawson | 47 30 52 N | 104 47 24 W |
| South Valley School (historical) | School | 828 | Dawson | 47 31 17 N | 104 48 02 W |
| South Van Houten Recreation Site | Locale | 2150 | Beaverhead | 45 14 38 N | 113 28 41 W |
| South Vananda School (historical) | School | 874 | Rosebud | 46 20 21 N | 106 59 12 W |
| South Wagner School (historical) | School | 690 | Phillips | 48 21 03 N | 108 05 09 W |
| South West Park | Park | 888 | Big Horn | 45 43 44 N | 107 37 06 W |
| South Whitey Coulee | Valley | | Garfield | 47 40 40 N | 106 51 16 W |
| South Willoughby Creek | Stream | | Ravalli | 46 26 41 N | 114 04 03 W |
| South Willow Creek | Stream | | Madison | 45 43 27 N | 111 44 44 W |
| South Willow Creek (historical) | School | 1447 | Carbon | 45 19 02 N | 109 16 30 W |
| South Wills Creek Oil Field | Oilfield | 892 | Fallon | 46 33 22 N | 104 22 40 W |
| South Wilson Coulee | Valley | | Garfield | 47 10 48 N | 107 54 53 W |
| South Woodward Creek | Stream | | Lake | 47 45 15 N | 113 51 28 W |
| South Yantic School (historical) | School | 752 | Blaine | 48 34 30 N | 109 19 06 W |
| Southeastern Montana Historical Marker | Park | 983 | Powder River | 45 27 50 N | 105 27 22 W |
| Southeastern Montana Research Library | Building | 724 | Custer | 46 24 43 N | 105 50 37 W |
| Southerd Homestead | Locale | 1838 | Park | 45 53 27 N | 110 19 14 W |
| Southerland Coulee | Valley | | Garfield | 47 12 33 N | 106 59 26 W |
| Southerland Lacosta Dam | Dam | 848 | Garfield | 47 13 18 N | 107 01 56 W |
| Southerland School (historical) | School | 860 | Garfield | 46 52 29 N | 106 13 54 W |
| Southern Comfort Ski Trail | Trail | 2150 | Ravalli | 45 41 35 N | 113 57 08 W |
| Southern Cross | Locale | 2125 | Deer Lodge | 46 12 37 N | 113 14 11 W |
| Southern Cross (historical) | Populated Place | 2125 | Deer Lodge | 46 12 37 N | 113 14 11 W |
| Southern Cross Post Office (historical) | Post Office | 2125 | Deer Lodge | 46 12 37 N | 113 14 11 W |
| Southern Cross School (historical) | School | 2125 | Deer Lodge | 46 12 37 N | 113 14 11 W |
| Southern Cross Ski Trail | Trail | 2175 | Granite | 46 15 23 N | 113 14 31 W |
| Southern Cross Spring | Spring | 1848 | Granite | 46 49 28 N | 113 23 23 W |
| Southern Flint Creek Valley Historical Marker | Park | 1286 | Granite | 46 34 40 N | 113 12 07 W |
| Southgate Mall | Locale | 969 | Missoula | 46 50 49 N | 114 01 30 W |
| Southmont Mine | Mine | 1844 | Beaverhead | 45 08 60 N | 112 58 03 W |
| Southside Detention Dam | Dam | 1458 | Carbon | 45 02 24 N | 108 33 56 W |
| Southside Lions Park | Park | 974 | Missoula | 46 51 05 N | 114 00 33 W |
| Southside Park | Park | 1482 | Gallatin | 45 40 18 N | 111 02 36 W |
| Southside RV Park | Locale | 1567 | Beaverhead | 45 12 18 N | 112 38 33 W |
| Southside School | School | 608 | Roosevelt | 48 05 16 N | 105 38 37 W |
| Southvale Post Office (historical) | Post Office | 1242 | Lewis and Clark | 47 29 25 N | 112 23 33 W |
| Southview School | School | 720 | McCone | 47 53 52 N | 105 23 18 W |
| Southwest Montana Radiology | Hospital | 1708 | Silver Bow | 46 00 25 N | 112 32 56 W |
| Southwick Creek | Stream | | Ravalli | 46 01 24 N | 114 11 15 W |
| Southwick School (historical) | School | 800 | Phillips | 48 17 59 N | 107 51 22 W |
| Sowa School (historical) | School | 647 | Valley | 48 22 16 N | 106 55 16 W |
| Spade Creek | Stream | | Ravalli | 45 54 55 N | 114 06 05 W |
| Spade Well | Well | 816 | Prairie | 46 54 04 N | 105 18 51 W |
| Spain (historical) | Locale | 1359 | Gallatin | 45 46 36 N | 111 06 38 W |
| Spain Bridge | Bridge | 1355 | Gallatin | 45 46 54 N | 111 06 48 W |
| Spain Ferris Ditch | Canal | 1403 | Gallatin | 45 43 04 N | 111 10 42 W |
| Spain Ferris Fork Ditch | Canal | 1363 | Gallatin | 45 46 17 N | 111 09 49 W |
| Spalding Post Office (historical) | Post Office | 1497 | Madison | 45 27 33 N | 111 43 45 W |
| Spang Creek | Stream | | Big Horn | 45 35 07 N | 106 44 48 W |
| Spang Spring | Spring | 1186 | Rosebud | 45 33 26 N | 106 33 14 W |
| Spaniard Dam | Dam | 1120 | Cascade | 47 13 18 N | 111 27 51 W |
| Spanish Breaks | Cliff | 2078 | Gallatin | 45 31 24 N | 111 17 40 W |
| Spanish Coulee | Valley | | Cascade | 47 16 10 N | 111 26 07 W |
| Spanish Coulee School (historical) | School | 1072 | Cascade | 47 12 40 N | 111 24 47 W |
| Spanish Creek | Stream | | Gallatin | 45 29 39 N | 111 16 17 W |
| Spanish Creek Basin | Basin | 1709 | Gallatin | 45 30 08 N | 111 21 07 W |
| Spanish Creek Forest Service Station | Locale | 1861 | Madison | 45 27 04 N | 111 22 25 W |
| Spanish Creek Ranch | Locale | 1591 | Gallatin | 45 29 38 N | 111 16 39 W |
| Spanish Creek Recreation Site | Locale | 1857 | Madison | 45 26 50 N | 111 22 42 W |
| Spanish Creek School (historical) | School | 1646 | Gallatin | 45 29 55 N | 111 19 03 W |
| Spanish Lakes | Lake | 2725 | Madison | 45 21 38 N | 111 25 18 W |
| Spanish Peaks | Range | 2573 | Madison | 45 23 13 N | 111 25 39 W |