Cockburn Island is an island 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.
Most of the island is incorporated as the municipal township of Cockburn Island, which had a permanent population of ten in the 2006 Canadian census.In the 2001 census the island's population had been reported as zero, due to Statistics Canada's counting method of rounding off population figures for communities of smaller than 15 people. It is the least populated incorporated municipality in Canada, and township offices are located on the mainland in Thessalon in the district of Algoma.
However, the population grows significantly in the summer, as an estimated two hundred people maintain cottages and summer homes on the island