Manitou Beach–Devils Lake is a census-designated place in Lenawee County in the U.S. state of Michigan. The population of the CDP was 2,032 at the 2020 census. It is located within Rollin Township to the south and Woodstock Township to the north. The census-designated place consists of the unincorporated communities of Devils Lake, Geneva, and Manitou Beach and includes the larger lakes of Devils Lake and Round Lake.