Beginning at Major Mackenzie Drive (York Regional Road 25), the route progresses northward from the rural–urban fringe of the Greater Toronto Area into farmland. A future extension of Donald Cousens Parkway will bypass former Highway 48 (Main Street) through downtown Markham in 2018 just north of Major Mackenzie. The route travels northward for along the 8th concession of York Region (Yonge Street being the 1st) to just south of , intersecting with Elgin Mills Road, former Highway 47 (Stouffville Road and Bloomington Road), York Regional Road 15 (Aurora Road), York Regional Road 74 (Vivian Road), York Regional Road 31 (Davis Drive), York Regional Road 13 (Mount Albert Road) and Queensville Sideroad along the way.