Forestry is the main economic activity in this valley; recreational tourism, second.

[1] The surface of the Franquelin Branche Ouest river is usually frozen from the beginning of November to the end of April, except the rapids; traffic on the ice is generally safe from late November to early April.

The Franquelin Branche Ouest river draws its source from a small lake (length: 0.13 km (0.081 mi); altitude: 430 m (1,410 ft)) located in the unorganized territory of Rivière-aux-Outardes.

This confluence is located on the west side of Cache-Trois, either: From the mouth of the West Branch Franquelin River, the current descends on 19.0 km (11.8 mi) the course of the Franquelin River to the north shore of the estuary of Saint Lawrence.

[2] The toponym "Franquelin Branche Ouest" was formalized on August 2, 1974, at the Place Names Bank of the Commission de toponymie du Québec.