Cass Lake is a city in Cass County, Minnesota, United States, within the reservation boundaries of the Leech Lake Band of the Ojibwe nation. The population was 860 at the 2000 census. The city is a Superfund site, due to toxic waste from the St. Regis Paper Company. The previous mayor, Elaine Fleming, is the first Native American to hold that position. Cass Lake is part of the Brainerd Micropolitan Statistical Area. Cass Lake is entirely within the borders of Pike Bay Township but is a separate entity from the township.