The forest road R0201 serves most of the hydrographic slope of the Saint-Louis river, for the needs of forestry and recreational tourism activities.

The mouth of this river flows to the northwest limit of the Monts-Valin National Park.

The main watersheds neighboring the Saint-Louis river are: The Saint-Louis river takes its source from an unidentified lake (length: 1.7 metres (5 ft 7 in); altitude: 691 metres (2,267 ft)).

This mouth is located at: The term "Saint-Louis" is a family name of French origin.

The toponym of “Saint-Louis river” was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.