Cockburn Island is an island and township municipality in the Canadian province of Ontario, located in the Manitoulin District. It is separated from the westernmost point of Manitoulin Island by the Mississagi Strait, and from Michigan's Drummond Island by the False Detour Channel. The island is incorporated as and coterminous with the municipal Township of Cockburn Island.

Manitoulin District is a district in Northeastern Ontario within the Canadian province of Ontario. It was created in 1888 from part of the Algoma District. The district seat is in Gore Bay.