Benton Township occupies the northeast corner of Cheboygan County, and is bordered to the north by the South Channel of the Straits of Mackinac opening out into Lake Huron. Presque Isle County is to the east, and Mackinac County is to the north. The city of Cheboygan borders the township on the northwest. The southwest corner of the township is in Mullett Lake, the outlet of which, the Cheboygan River, forms the western border of the township up to the city of Cheboygan. The Black River enters the township from the south and flows northwest to the Cheboygan River at the township's western border.