The Leblanc River is a tributary of the De La Galette River, flowing on the south shore of the Gouin Reservoir, in the territory of the town of La Tuque, in the Mauricie administrative region, in Quebec, in Canada.

The route 400, connecting Gouin Dam to the village of Parent, Quebec, serves the Leblanc River Valley; this road also serves the peninsula which stretches north in the Gouin Reservoir on 30.1 kilometres (18.7 mi).

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

The Leblanc River originates at the mouth of Decelles Lake (length: 5.7 kilometres (3.5 mi); altitude: 435 metres (1,427 ft)).

The toponym "Leblanc River" was formalized on August 17, 1978 at the Commission de toponymie du Quebec.