The Bras de Riche (in English: Arm of Rich) flows in the municipalities of Saint-Cyrille-de-Lessard, Saint-Aubert and L'Islet (Saint-Eugène sector), in the L'Islet Regional County Municipality, in the administrative region of Chaudière-Appalaches, in Quebec, in Canada.

The "Bras de Riche" is a tributary of the east bank of the Bras Saint-Nicolas, which flows on the south-east bank of the rivière du Sud (Montmagny); the latter flows north-east to the south shore of the St. Lawrence River.

The main neighboring watersheds of Bras de Riche are: The "Bras de Riche" takes its source at Lake Bringé (length: 0.8 kilometres (0.50 mi); altitude: 517 metres (1,696 ft)), located in a mountainous area, located at the limit between Saint-Cyrille-de-Lessard and Saint-Aubert.

This head lake is located southeast of Trois Saumons lake and 12.3 kilometres (7.6 mi) southeast of the south shore of the St. Lawrence River.

This confluence is located upstream from the bridge at a place called "Les Chandelles", downstream from the "Toupin waterfall" and 2.9 kilometres (1.8 mi) north-west of the center of the village of Saint-Cyrille-de-Lessard.