It progresses north through an isolated region dominated by the forests, exposed bedrock, rivers, numerous lakes, muskeg and mountains of the Canadian Shield, encountering no communities or significant roads along its 151.1-kilometre (93.9 mi) route; it does provide access to numerous logging and mineral access roads.

[6][7][8][9] The new route reduced the distance between Marysville and Napanee by nearly 5 km (3 mi).

[10] The section of Highway 401 parallel to Belleville Road was one of the final links in the trans-provincial freeway.

The existing Highway 812 extended north from Highway 11 for approximately 50 kilometres (30 mi), and so work began to extend it north the remaining 100 kilometres (62 mi).

[2] The Manitou Road was officially opened on October 31, 1980, and redesignated as Highway 502.

[17] The following table lists the major junctions along Highway 502, as noted by the Ministry of Transportation of Ontario.