The Cedars River flows through the municipalities of Saint-Agapit, Saint-Flavien, Dosquet, Saint-Janvier-de-Joly and Val-Alain, in the MRC of Lotbinière Regional County Municipality, in the administrative region of Chaudière-Appalaches, in Quebec, in Canada.

The main neighboring watersheds of the Cèdres river are: The Rivière aux Cèdres has its source in a marsh area straddling the intermunicipal boundaries of Saint-Agapit, Dosquet and Saint-Flavien.

This head area is located 8.0 kilometres (5.0 mi) southwest of the center of the village of Saint-Agapit, at 5.5 kilometres (3.4 mi) west of the village center of Saint-Flavien and at 5.0 kilometres (3.1 mi) northeast of the center of the village of Dosquet.

From its head area, the Rivière aux Cèdres flows over 20.9 kilometres (13.0 mi) with a drop of 67 metres (220 ft), divided into the following segments: The Rivière aux Cèdres flows into a bend in the river on the east bank of the Henri River in the municipality of Val-Alain.

The toponym Rivière aux Cèdres was formalized on December 5, 1968, at the Commission de toponymie du Québec.