The Subercase River is a tributary of Grasset Lake (watershed of Nottaway River, in the Nord-du-Québec administrative region, in the Canadian province of Quebec, in Canada.

The course of the river crosses the townships of Desmazures, Daloigny, La Gauchetière, Saint Hélène, Subercase and Grasset.

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

The main neighboring hydrographic slopes are: The "Subercase River" originates from a forest stream located at: From its source in the township of Desmazures, the Subercase River flows over 83.5 kilometres (51.9 mi), especially in the marsh zone, according to the following segments: The Subercase River empties onto the South bank of the Nottaway River.

This confluence is located at: The term "Subercase" is a family name of English origin.