The Flapjack River is a tributary of the Mattawa Bay of the Southwest of Gouin Reservoir, flowing into the town of La Tuque, into the administrative area of the Mauricie, in Quebec, in Canada. The Flapjack River flows successively into the townships of Buies, Provencher and Poisson. Forestry is the main economic activity of this valley; recreational tourism activities, second. The surface of the Flapjack River is usually frozen from mid-November to the end of April, however, safe ice movement is generally from early December to late March.