Highway 651 is a 52.8-kilometre (32.8 mi) route which connects the community of Missanabie with Highway 101, also providing access to the western side of the Chapleau Crown Game Preserve. The southern terminus of the route is a junction with Highway 101, midway between Wawa and Chapleau. From there it proceeds north through an isolated region of northern Ontario, passing through the thick forests of the Canadian Shield. At the midpoint of the route, a short road branches off to the east, connecting with Dalton, a siding on the Canadian Pacific Railway's transcontinental line. North of Dalton, the railway — which acts as the southwestern boundary of the preserve — and highway travel parallel to one another. The route ends immediately east of Missinabie.^[3]

Highway 651 was assumed by the Department of Highways (DHO) on the day of Canada's Centennial, July 1, 1967. At that point in time, Highway 101 had not yet been completed between Wawa and Chapleau, and so the route was connected to the rest of the province solely by rail. The isolated highway provided access between the community of Missanabie and the flag stop at Dalton, to the south. It was approximately half of the current length of the route.^[2]

Highway 651 was assumed by the DHO on the same day as the section of Highway 101 between Wawa and Chapleau opened, though it did not connect to it at first. A southward extension of Highway 651 to intersect it opened to traffic on April 30, 1969.^[2] The route has remained unchanged since that time.^[3]

The following table lists the major junctions along Highway 651, as noted by the Ministry of Transportation of Ontario.^[1] The entire route is located in Algoma District.^[3]