The bras de Jacob (English: Jacob's arm) is a tributary of the rivière du Moulin, flowing successively in the Saguenay, then in the territory not organized from 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.

The upper part of this small valley is served by the Lac-du-Bois-Joli road which passes on the north shore of Lac Jacob.

A few other secondary forest roads serve the valley of the Jacob's arm, mainly for forestry and recreational tourism activities.

The surface of Jacob's arm 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 mouth of "Bras de Jacob", the current successively follows the course of the rivière du Moulin on 37.6 km (23.4 mi) towards the north, then the course from the Saguenay River on 126.1 km (78.4 mi) eastwards to Tadoussac where it merges with the Saint Lawrence Estuary.