Lonepine is a census-designated place (CDP) in Sanders County, Montana, United States.

[3] In 1921, the U.S. Reclamation Service built the Lower Dry Fork Reservoir to provide irrigation for the region.

This climatic region is typified by large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold) winters.

22.2% of all households were made up of individuals, and 5.6% had someone living alone who was 65 years of age or older.

There were 9.8% of families and 6.3% of the population living below the poverty line, including no under eighteens and none of those over 64.