The Sunday River (in French: rivière Sunday) is a tributary of the Osgood River, whose course flows successively into the Palmer River and Bécancour River; the latter being in turn a tributary of the south shore of the St. Lawrence River. The Sunday River flows through the municipalities of Kinnear's Mills and Saint-Jacques-de-Leeds, in the Les Appalaches Regional County Municipality (MRC), in the region administrative office of Chaudière-Appalaches, in Quebec, in Canada.