Cass Lake is a city in Cass County, Minnesota, United States, located within the boundaries of the Leech Lake Indian Reservation. It is surrounded by Pike Bay Township. Cass Lake had a population of 770 in the 2010 census. It is notable as the headquarters location of Minnesota Chippewa Tribe and Leech Lake Band of Ojibwe, as well as the Chippewa National Forest.The city is located on the shore of its namesake Cass Lake, which was named in honor of Michigan Governor Lewis Cass.Cass Lake is part of the Brainerd Micropolitan Statistical Area. It reached its peak of population of over 2,100 in 1920. Since 1950, the combination of decline of small town retailers, suburbanization, and decreased employment in forest industries have resulted in steadily decreasing population.