Papineau Avenue, (officially Avenue Papineau in French) is an important, and longest, north-south street in Montreal, Quebec, Canada. Part of the street, between Henri Bourassa Boulevard and Quebec Autoroute 40, is the Montreal portion of Quebec Autoroute 19, commonly referred to as Autoroute Papineau. North of Henri Bourassa Boulevard it becomes a true autoroute before crossing the Rivière des Prairies on the Papineau-Leblanc Bridge.