| Rivière du Sud | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Quebec |
| Subdivision Type3: | Region |
| Subdivision Name3: | Chaudière-Appalaches |
| Subdivision Type4: | Regional County Municipality |
| Subdivision Name4: | Montmagny Regional County Municipality |
| Length: | 86.5km (53.7miles) |
| Source1: | Forested streams |
| Source1 Location: | Notre-Dame-du-Rosaire |
| Source1 Coordinates: | 46.851°N 70.335°W |
| Source1 Elevation: | 440m (1,440feet) |
| Mouth: | Saint Lawrence River |
| Mouth Location: | Montmagny |
| Mouth Coordinates: | 46.9861°N -70.5508°W |
| Mouth Elevation: | 4m (13feet) |
| Tributaries Left: | (Upstream) Rivière du Vieux Moulin, Bras Saint-Michel, Rivière du Moulin, cemetery stream, outlet of the lake at Beaulieu, Roy stream, Fourche River, rivière du Pin, rivière à la Loutre, Alick River, Fraser River. |
| Tributaries Right: | (Upstream) Bras Saint-Nicolas, Prairies stream, Rousseau stream, Blague stream, Miscou stream, Morigeau River, Campagna-Théberge stream, Théberge stream, Little Sainte-Marguerite River, Noire River, Isabelle stream, Beaver outlet, Laflamme outlet, Grand Ruisseau, Ferré stream. |
The rivière du Sud (English: River of the South) is a tributary of the south shore of the Saint Lawrence River. This watercourse flows in the municipalities of Notre-Dame-du-Rosaire, Sainte-Euphémie-sur-Rivière-du-Sud, Armagh, Saint-Raphaël, Saint-François-de-la-Rivière-du-Sud, Saint-Pierre-de-la-Rivière-du-Sud and Montmagny, in the Montmagny Regional County Municipality, in the administrative region of Chaudière-Appalaches, in the province of Quebec, in Canada.
The South River has its source in rang Saint-Thomas, in the township of D'Ashburton, in the municipality of Notre- Dame-du-Rosaire 25 km south-east of Montmagny. This source is located in a forest and mountain area on the southwest slope of a mountain. The south river "first flows south-east along the Appalachian mountain lines, then makes a large curve towards the north-east to orient itself more or less parallel to the south bank of the Saint Lawrence River.
From its source, the South River flows on 86.5 km, with a drop of, divided into the following segments:
Upper course of the river (50.6 km segment)
Lower course of the river (35.9 km segment)
At the end of its course, after having crossed a fall from a height of seven meters, the South River flows into Le Bassin, on the long strike of the Banc de Saint-Thomas, on the south bank of the St. Lawrence River, in the heart of the village of Montmagny. This confluence which includes the bird sanctuary of Montmagny is located opposite the channel of Saint-Thomas.
Probably called "S. Antoine river" by Samuel de Champlain on his 1632 map, and "R. de S. Anthome" by Jean Boisseau, in 1643, the South river "seems to appear on the map from Jean Bourdon, drawn up around 1641, in the form of Grande Rivière du Sud. The act of concession of the seigneury of Rivière-du-Sud to Charles Huault de Montmagny, in 1646, expressly states "the river called from the South to the point where it discharges into the Saint Lawrence River. Very stable thereafter, the toponym is part of the official designation of three municipalities drained by this course of water: Saint-Pierre-de-la-Rivière-du-Sud, Saint-François-de-la-Rivière-du-Sud and Sainte-Euphémie-sur-Rivière-du-Sud.[1]
The toponym Rivière du Sud was formalized on December 5, 1968 at the Commission de toponymie du Québec.[2]