Lac-Ashuapmushuan is an unorganized territory in the Canadian province of Quebec, Canada, located in the regional county municipality of Le Domaine-du-Roy.

The region had a population of 41 as of the 2021 Canadian census, and covered a land area of 14,684.28 square kilometres (5,669.63 sq mi).

[5] In 1685, French fur traders set up a trading post near Lake Ashuapmushuan that remained almost continuously in operation until the middle of the 19th century.

This river flows into Lake Saint-Jean and was frequently traveled by fur traders at the time of the New France and also the English regime, in order to make commercial treaties, especially human trafficking fur.

This river was a preferred axis to connect in canoes between Lac Saint-Jean and James Bay.