It flows in the municipalities of Saint-Alfred and Beauceville, in the Robert-Cliche Regional County Municipality, in the administrative region of Chaudière-Appalaches, in Quebec, in Canada.

The main neighboring watersheds of the Moulin river are: 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 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.

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.