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

From there, the current flows first north through the Waswanipi River, then west to the east shore of Goéland Lake.

The name of this river evokes a missionary active in the region in the nineteenth century; in 1905, Henry O'Sullivan announced his presence at Fort Eastmain.

A natural extension of [Mistassini Lake], called Baie Iserhoff, also evokes Charles Iserhoff, nephew of this missionary employed by the Hudson's Bay Company, at the former trading post of Baie-du-Poste; this site has become today the Cree village of Mistissini.

Jacques and Madeleine Rousseau used in 1946 the services of an informant (born Iserhoff), and then bearing the name of Mrs. Wilfrid Jefferys; according to his testimony, the members of this Métis family have always lived at either the Mistassini Lake or the Waswanipi station.