The Mistaouac River is a tributary of the Wawagosic River, flowing into the municipality of Eeyou Istchee Baie-James (municipality), in the administrative region of Nord-du-Québec, in Quebec, in Canada.

The course of the river Mistaouac successively crosses the townships of Estrades, Orvilliers, Puiseaux and Brouillan.

The surface of the river is usually frozen from the end of November to the end of April, however safe ice circulation is generally from early December to mid-April.

The hydrographic slopes near the Mistaouac River are: The Mistaouac River has its source at the mouth of Lake Villaret (length: 3.9 kilometres (2.4 mi) altitude: 290 metres (950 ft)) in the canton of Orvilliers which is surrounded by several zones marsh.

This lake is located at: From its source, the "Mistaouac river" flows over 36.9 kilometres (22.9 mi) entirely in forest zone according to these segments: The mouth of the "Mistaouac River" which flows on the East bank of the Wawagosic River is located in the forest zone at: The mouth of the river is called Nekuwacka confluence in the Algonquin language.