| Official Name: | Mammoth, Montana |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Montana#USA |
| Pushpin Label: | Mammoth |
| Coordinates: | 45.6672°N -112.0186°W |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Montana |
| Subdivision Type2: | County |
| Subdivision Name2: | Madison |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Sq Mi: | 0.35 |
| Area Land Sq Mi: | 0.35 |
| Area Water Sq Mi: | 0.00 |
| Area Total Km2: | 0.91 |
| Area Land Km2: | 0.91 |
| Area Water Km2: | 0.00 |
| Population As Of: | 2020 |
| Population Total: | 4 |
| Population Footnotes: | [2] |
| Population Density Sq Mi: | 11.43 |
| Population Density Km2: | 4.41 |
| Timezone: | Mountain (MST) |
| Utc Offset: | -7 |
| Timezone Dst: | MDT |
| Utc Offset Dst: | -6 |
| Elevation Ft: | 6016 |
| Postal Code Type: | ZIP Codes |
| Postal Code: | 59721 (Cardwell) 59747 (Pony) |
| Area Code: | 406 |
| Blank Name: | FIPS code |
| Blank Info: | 30-47460 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2806644 |
Mammoth is an unincorporated community and census-designated place (CDP) in Madison County, Montana, United States. It is in the northern part of the county, in the valley of the South Boulder River within the northern end of the Tobacco Root Mountains. Via the South Boulder River, it is part of the Jefferson River watershed, one of the headwaters of the Missouri River.
Mammoth is reached by South Boulder Road, which leads north to Montana Highway 359 at a point 5miles south of Cardwell.
Mammoth was first listed as a CDP prior to the 2020 census, when it had a population of 4.[2]