Autoroute 640 (or A-640) is a provincial superhighway that runs across the North Shore Region (paralleling the Rivière des Mille-Îles) from Route 344 in the Oka area to Route 138, where it ends as a four-lane expressway in Charlemagne. It was designed as a northern bypass to Montreal and was originally intended to cross the Lake of Two Mountains to connect to Autoroute 40 near Vaudreuil, but that section is unlikely to be constructed.