Ontario Provincial Highway Network

The Ontario Provincial Highway Network consists of all the roads in Ontario maintained by the Ministry of Transportation (MTO), including those designated as part of the King's Highway, secondary highways, and tertiary roads. Components of the system—comprising 16,900 kilometres (10,500 mi) of roads and 2,880 bridges—range in scale from Highway 401, the busiest highway in North America, to unpaved forestry and mining access roads.

Source: Wikipedia — Ontario Provincial Highway Network (CC BY-SA 4.0)