The Moulin river has its source at Volet lake (length: 0.8 kilometres (0.50 mi); altitude: 265) which is located in rang Saint-Guillaume de Saint-Alfred. This lake is located at 2.0 kilometres (1.2 mi) south-east of the center of the village of Saint-Alfred, at 6.5 kilometres (4.0 mi) west of the Chaudière River, at 7.1 kilometres (4.4 mi) north of the center of the village of Saint-Benoît-Labre and at 0.6 kilometres (0.37 mi) north of the municipal boundary of Saint-Benoît-Labre (MRC Beauce-Sartigan Regional County Municipality).
Lake Volet is fed by the Bernard stream (coming from the east) and the "discharge of Lake Fortin" (coming from the southwest). Lake Fortin (length: 2.4 kilometres (1.5 mi); altitude of 310 metres (1,020 ft)) is renowned for its vacation; this head lake is located 4.1 kilometres (2.5 mi) southeast of the village of Saint-Victor.
From its source, the Moulin river flows over 8.4 kilometres (5.2 mi) divided into the following segments:
1.5 kilometres (0.93 mi) northward, delimiting rang Saint-Guillaume (west side) and rang Clark (east side), to the confluence of the Noire River;
2.8 kilometres (1.7 mi) northeasterly, up to the municipal limit between Saint-Alfred and Beauceville;
3.0 kilometres (1.9 mi) northward, to the confluence of ruisseau des Meules;
1.2 kilometres (0.75 mi) towards the northeast, crossing avenue Lambert which runs along the west bank of the Chaudière River, up to its confluence.[1]
The Moulin river flows on the west bank of the Chaudière River in the municipality of Beauceville. The confluence of the Rivière du Moulin is located 0.7 kilometres (0.43 mi) south of the town of Beauceville bridge and downstream from Île aux Oies.