This river flows in the municipalities of Milan (MRC Le Granit Regional County Municipality) and Lingwick (MRC) Le Haut-Saint-François Regional County Municipality), in the administrative region of Estrie, in the province of Quebec, in Canada.

[2] The surface of the Salmon River is usually frozen from mid-December to mid-March, except the rapids areas; however, safe circulation on the ice is generally from late December to early March.

[2] From its source, the Red River flows over 26.3 km (16.3 mi), with a drop of 259 m (850 ft), according to the following segments: The red river flows on the northeast bank of the rivière au Saumon.

This confluence is located 3.9 km (2.4 mi) north-west of the center of the village of Lingwick.

The toponym "Rivière Rouge" was formalized on December 18, 1979, at the Commission de toponymie du Québec.