Western Terminus: Ontario Highway 417 at the Ontario/Quebec Border

Eastern Terminus: Route 138 near Boischatel, east of Quebec City 

Routing: A-40 starts at the Ontario/Quebec Boundary as a continuation of Ontario's Highway 417.  From Ontario to Montreal, A-40 carries the Trans-Canada Highway designation, and runs to the north of the Ottawa River.  Through Montreal Autoroute 40 follows the very congested Metropolitan Autoroute.  The Trans-Canada Highway designation departs A-25 in eastern Montreal.  Beyond Montreal, A-40 continues along the north shore of the Saint Lawrence River, jogging through Downtown Trois-Rivières along what was first proposed as a spur route from Autoroute 55.  East into Quebec City, Autoroute 40 by-passes the City to the north, following the Autoroute 73 alignment.  A-40 terminates just east of Quebec City where the Highway transitions into Route 138.  Route 138 continues east of Quebec City almost to Labrador along the north shore of the St. Lawrence.