The Saint-Jean River is served primarily by route 170 (east-west), which passes through the hamlets "Le Ruisseau-du-Portage" and "La Chute-à-Salum".

Some other secondary forest roads serve the lake area mainly for forestry and recreational tourism purposes.

Three watersheds drain the territory of Zec du Lac-Brebeuf, which are the Saint-Jean rivers and its tributaries, Cami and Catin.

The toponym "Rivière Saint-Jean" appears as early as 1731 in Louis Aubert's Journal de Lachesnaye (transcript of Serge Goudreau).

The toponym "Saint-Jean River" (Saguenay) was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.