M-61 starts in eastern Osceola County south of Marion at an intersection with M-115. It runs eastward and meets M-66 before crossing into Clare County. The highway runs along the boundary between the regions of Northern and Central Michigan through forest land and crosses the Muskegon River en route to Harrison. There it follows Main Street into town to an intersection with 1st Street near Budd Lake. M-61 turns south at the intersection and joins the business loop of US 127 (Bus. US 127) through town. Bus. US 127/M-61 follows Clare Avenue south of the city to exit 170 on the US 127 freeway. The business loop ends, and M-61 turns east along Gladwin Road.