It empties into the municipality of Nicolet, in the Nicolet-Yamaska Regional County Municipality (MRC), in the administrative region of Centre-du-Québec, in Quebec, in Canada.

This river flows through the regional county municipalities (MRC): Administrative region of Estrie: Administrative region of Centre-du-Québec: The main neighboring hydrographic slopes of the Nicolet Sud-Ouest river are: The "Nicolet Sud-Ouest River" has its source at "Lac chez Piet" located between two mountains in the territory of the municipality of Dudswell.

This spring is located at 6.2 kilometres (3.9 mi) south of the village of Saint-Camille, at 1.2 kilometres (0.75 mi) east of the route 216, at 1.4 kilometres (0.87 mi) east of Lake Watopeka and 8.5 kilometres (5.3 mi) south-west of the center of the village of Saint-Adolphe-de-Dudswell.

Upper course of the river (segment of 58.8 kilometres (36.5 mi)) From "Lac chez Piet", the "Nicolet Sud-Ouest" river flows over: Intermediate course of the river (segment of 39.3 kilometres (24.4 mi)) From the village of Kingsey Falls, the Nicolet Sud-Ouest river flows over: Lower course of the river (segment of 41.1 kilometres (25.5 mi)) From highway 20, the river flows over: The "South-West Nicolet River" empties on the west bank of the Nicolet River, at 3.7 kilometres (2.3 mi) upstream of Moras Island, at 200 metres (660 ft) downstream of the Île de l'Île bridge and 2.0 kilometres (1.2 mi) upstream of the Pierre-Roy bridge (route 132).

[1] The main tributaries of the Nicolet Sud-Ouest river are: The toponym "Rivière Nicolet Sud-Ouest" was formalized on December 5, 1968, at the Commission de toponymie du Québec.