Sugar Island Township is a civil township of Chippewa County in the U.S. state of Michigan. The population was 653 at the 2020 census. The township consists of Sugar Island, several smaller islands, and the surrounding waters in the St. Marys River.

Chippewa County is a county in the eastern Upper Peninsula of the U.S. state of Michigan. As of the 2020 census, the population was 36,785. The county seat is Sault Ste. Marie. The county is named for the Ojibwe (Chippewa) people, and was set off and organized in 1826. Chippewa County comprises the Sault Ste. Marie, MI micropolitan statistical area.