| Lonesome Mountain | |
| Elevation Ft: | 11399 |
| Elevation Ref: | [1] |
| Prominence Ft: | 1039 |
| Isolation Mi: | 2.43 |
| Isolation Ref: | [2] |
| Parent Peak: | Spirit Mountain (12,283 ft) |
| Map: | Montana#USA |
| Map Size: | 270 |
| Label Position: | top |
| Location: | Carbon County, Montana, U.S. |
| Range: | Rocky Mountains Absaroka Range Beartooth Mountains |
| Coordinates: | 45.0143°N -109.5952°W |
| Topo: | USGS Silver Run Peak |
| Easiest Route: | scrambling |
Lonesome Mountain is an 11399abbr=offNaNabbr=off mountain summit located in Carbon County, Montana.[3]
Lonesome Mountain is located in the Beartooth Mountains, which are a subset of the Rocky Mountains. It is situated 4.2 miles north of Beartooth Butte in the Absaroka-Beartooth Wilderness, on land managed by Gallatin National Forest. The highest point in Montana, Granite Peak, rises 14.3 miles to the northwest. Precipitation runoff from the mountain drains into several surrounding alpine lakes which feed tributaries of the Clarks Fork Yellowstone River. Topographic relief is significant as the summit rises 1400abbr=offNaNabbr=off above these lakes in less than one mile. This geographical feature's name has been officially adopted by the United States Board on Geographic Names.[3]
Based on the Köppen climate classification, Lonesome Mountain is located in a subarctic climate zone characterized by long, usually very cold winters, and mild summers.[4] Winter temperatures can drop below −10 °F with wind chill factors below −30 °F.