The rivière du Milieu (English: River of the Middle) flows in the unorganized territory Baie-de-la-Bouteille, in the Matawinie Regional County Municipality, in the administrative region of Lanaudière, in the province of Quebec, in Canada.

From the end of the XIXth, the economy of the sector was centered on forestry.

The Milieu River (Lanaudière) has its source at Lake Hastel (1.9 km (1.2 mi) long, facing south), in the unorganized territory Baie-de-la-Bouteille at 474 m (1,555 ft) of altitude.

The watershed on the northeast side of this lake is the Alexandrine River.

Course downstream from Lake Hastel From the mouth of Lake Hastel (south-eastern point), the Milieu river descends on: Course downstream from Lac Chantier From the mouth of Chantier Lake, the river descends: Course downstream from Lake Charland From the mouth of Charland Lake, the river flows down to: The Rivière du Milieu descends southward entirely into the unorganized territory of Baie-de-la-Bouteille, crossing the Blueberry, Perrault and Brochet rapids.