Don Mills Road is a north-south route in Toronto, Ontario, Canada, passing through the former cities of East York and North York. It begins at O'Connor Drive near ramps to the Don Valley Parkway, and ends at John Street in Markham, where it becomes a separate northern section of Leslie Street, which parallels it to the west south of the break. North of Steeles Avenue, the road is designated and signed as York Regional Road 12, which continues along Leslie.