Wels (vĕls) [key], city (1991 pop. 52,594), Upper Austria province, W Austria, on the Traun River. It is an industrial and rail center and an agricultural market. Manufactures include agricultural machinery, building materials, food products, pharmaceuticals, and textiles. Nearby are natural gas wells. A town in Roman times, Wels later became a stronghold against the Avars and the Magyars. Noteworthy buildings include the parish church and the castle where Emperor Maximilian I died in 1519.