Lac-au-Saumon is a municipality in the Canadian province of Quebec, located in La Matapédia Regional Council Municipality in the Matapédia Valley. The municipality had a population of 1,488 as of the Canada 2021 Census. The village is located on the shores of the eponymous Lac au Saumon (French for "Salmon Lake") that is an enlargement of the Matapédia River. It was known as a spawning ground for salmon, but major pollution from mills made this a thing of the past.