Mountain Lake is a city in Cottonwood County, Minnesota, United States. The population was 2,104 at the 2010 census. Mountain Lake was initially composed mostly of the 1,800 Low German speaking Mennonites from Russia who settled there between 1873 and 1880. Although the city has gradually become more diverse, with the more recent addition of immigrant groups including Lao, Hmong, and Hispanic people, a significant percentage of its inhabitants still have Mennonite surnames.