Manitou County was an insular county in the U.S. state of Michigan, consisting of Beaver Island and its surrounding islands, together with the North and South Manitou Islands and Fox Islands in Lake Michigan. The county existed from 1855 to 1895. The county seat was at St. James on Beaver Island.
In this 1872 map, one can see the three clusters of islands that comprised Manitou County: the Beaver Island Archipelago (labeled), then Fox Islands (north of Leelanau county), and North Manitou Island & South Manitou Island (to the left of Northport)