Autoroute 31 (A-31) is an Autoroute in the region of Lanaudière in Quebec. Constructed in 1966, the A-31 primarily links Joliette with the A-40 and in turn to Montreal, Trois-Rivières, and other points served by Quebec's autoroute system. The A-31 is only 14 km (8.7 mi) long, making it one of the shortest autoroutes in the province.