Unorganized Mainland Manitoulin was an unorganized area in the Canadian province of Ontario, encompassing the small mainland portion of the Manitoulin District which was not part of the municipality of Killarney.

[3] It comprised the geographic townships of Carlyle and Humboldt, as well as the unpopulated Indian reserve of Point Grondine.

The only named settlement within the division is the ghost town of Collins Inlet.

Prior to the incorporation of Killarney in 1999, the unorganized territory had an area of 772.86 square kilometres (298.40 sq mi).

[4] The division had a population of five in the Canada 2006 Census, and a land area of 140.45 square kilometres (54.23 sq mi).