The Inconnue River (French: Rivière Inconnue) is a tributary of the Maicasagi River located in the municipality of Eeyou Istchee Baie-James, in the administrative region of Nord-du-Québec, in the Canadian province of Quebec, in Canada.

The course of the Inconnue River crosses the townships of Ribourde, Daine, Krieghoff, Montalambert, La Rouvillière and Monseignat.

The surface of the Inconnue River is usually frozen from early November to mid-May, however, safe ice movement is generally from mid-November to mid-April.

The main hydrographic slopes near the Inconnue River are: The Inconnue River originates at the mouth of Lac La Ribourde (length: 4.2 kilometres (2.6 mi) altitude: 335 metres (1,099 ft)).

The mouth of the Rivière Inconnue located at: The toponym "Rivière Inconnue" was officialized on December 5, 1968, at the Commission de toponymie du Québec, i.e. at the creation of this commission[3] Download coordinates as: