It flows in the municipalities of Saint-Julien and Irlande, in the Les Appalaches Regional County Municipality (MRC), in the administrative region of Chaudière-Appalaches, in Quebec, in Canada.

The main neighboring watersheds of the Larochelle river are: The Larochelle River has its source in the mountains, 1.7 kilometres (1.1 mi) west at the village of Saint-Julien, 4.1 kilometres (2.5 mi) northeast of the village of Saint-Fortunat and 7.9 kilometres (4.9 mi) northwest of the village of Saint-Jacques-le-Majeur-de-Wolfestown.

From its head, the Larochelle river flows over 15.7 kilometres (9.8 mi) divided into the following segments: The Larochelle river empties on the west bank of the Bécancour River.

This confluence is located 1.1 east of the hamlet "Maple Grove", 0.6 kilometres (0.37 mi) upstream from "Lac à la Truite" and 3.6 kilometres (2.2 mi) in upstream of William Lake.

The toponym "rivière Larochelle" was made official on August 17, 1978, at the Commission de toponymie du Québec.