M-105 started at an intersection with M-53 (Van Dyke Road) in the community of Popple, just before M-53 curved east towards Bad Axe. M-105 was known as Pinnebog Road. The trunkline traveled north and then northwest, and crossed the Pinnebog River. After intersecting Stein Road, M-105 turned north for about through farm country and rural areas before meeting M-83 (Pigeon Road), a few miles east of Elkton. The highway was used as a shortcut between M-53 and M-83.