The Bras des Mouches is a tributary of the Bras d'Isaïe, flowing in the unorganized territory of Lac-Ministuk, in the Le Fjord-du-Saguenay Regional County Municipality, in the administrative region of Saguenay–Lac-Saint-Jean, in the province of Quebec, in Canada.

Some secondary forest roads serve the "Bras des Mouches" valley, especially for forestry and recreational tourism activities.

The surface of the "Bras des Mouches" is usually frozen from the beginning of December to the end of March, however the safe circulation on the ice is generally done from mid-December to mid-March.

This confluence is located at: From the confluence of the arm of the Flies with the rivière à Mars, the current follows the course of the bras d'Isaïe on 3.0 km (1.9 mi) towards the east, the course from the rivière à Mars on 10.9 km (6.8 mi) generally towards the north, crosses Baie des Ha!

[3] The toponym "bras des Mouches" was formalized on June 29, 1983, at the Place Names Bank of the Commission de toponymie du Québec.