| Saint-Louis River | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Quebec |
| Subdivision Type3: | Region |
| Subdivision Name3: | Montérégie |
| Subdivision Type4: | MRC |
| Subdivision Name4: | Pierre-De Saurel Regional County Municipality |
| Length: | 22km (14miles) |
| Discharge1 Avg: | NaNm3/s |
| Source1: | Various agricultural streams |
| Source1 Location: | Saint-Aimé |
| Source1 Coordinates: | 45.8446°N -72.9966°W |
| Source1 Elevation: | 29 |
| Mouth: | Le Petit Chenail |
| Mouth Location: | Yamaska |
| Mouth Coordinates: | 46.0261°N -72.9208°W |
| Mouth Elevation: | 18m (59feet) |
| Basin Size: | NaNkm2 |
The Saint-Louis river is a tributary of the Yamaska River, through the Petit Chenail. This river flows northeast in the municipalities of Saint-Aimé and Yamaska in the Pierre-De Saurel Regional County Municipality, in the administrative region of Montérégie, on the South Shore of the St. Lawrence River, in the province of Quebec, Canada.
The main hydrographic slopes neighboring the Saint-Louis river are:
The Saint-Louis river rises in Rang Prescott just north of the "cordon discharge", southwest of the village of Saint-Louis-de-Bonsecours and north of the village of Saint-Louis.
From its head, the Saint-Louis river flows on:
The Saint-Louis river flows on the west bank of the Le Petit chenail, 1.4 km upstream from the outlet of the channel which connects to the west bank of the Yamaska River. The mouth of the Saint-Louis river is located east of Sorel-Tracy, 3.0 km north of the Camille-Parenteau Bridge located in the village of Yamaska and 11.7 km north of the village center of Massueville.[1]
Formerly, this river was designated "rivière des Pins Verts" (English: Green Pine River).
The toponym "Saint-Louis" was officially registered on December 5, 1968 at the Commission de toponymie du Québec.[2]