The area of the upper Saint-Maurice River had long been the homeland and hunting grounds of the Atikamekw indigenous people. Some sources claim that the
North West Company had already established a trading post at this place between 1770 and 1780, but this remains doubtful. Confirmation of the existence of a trading post at Wemotaci came in 1806, when
Jean-Baptiste Perrault built the first structures for fur trading. In 1821, the post was taken over by the
Hudson's Bay Company. But the Atikamekw didn't give up their nomadic life and settle on the reserve. And it wasn't until 1895 that the reserve was surveyed. The construction of a dam and the
National Transcontinental Railway led to the growth of the Sanmaur settlement, which in turn attracted the Atikamekw to the reserve at the beginning of the 20th century. In 1939 however, the Hudson's Bay Company left Weymontachingue and due to lack of funding for maintenance of the village, its population stopped growing after 1950, when its inhabitants began to leave and settled either in Sanmaur or in other nearby villages. ==Demographics==