| Boyer South River | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Quebec |
| Subdivision Type3: | Region |
| Subdivision Name3: | Chaudière-Appalaches |
| Subdivision Type4: | Bellechasse Regional County Municipality et Desjardins Regional County Municipality |
| Subdivision Name4: | MRC |
| Source1: | Agricultural streams |
| Source1 Location: | Honfleur |
| Mouth: | Boyer River |
| Mouth Location: | Saint-Charles-de-Bellechasse |
| Progression: | St. Lawrence River |
| Tributaries Left: | (upstream) |
The Boyer South River (in French: rivière Boyer Sud) is a tributary of the Boyer River, which flows northeast and empties on the south shore of the St. Lawrence River. The South Boyer River crosses the municipalities of Honfleur, Saint-Gervais, Saint-Henri and Saint-Charles-de-Bellechasse, in the Bellechasse Regional County Municipality, in the administrative region of Chaudière-Appalaches, in Quebec, in Canada.
The main neighboring watersheds of the South Boyer River are:
The Boyer Sud river has its source in an agricultural zone on the north side of the village of Honfleur, in the 3e rang East, between the third rang East road and the path "la Petite 3e".
From its source, the South Boyer River flows on, with a drop of, according to the following segments:
The confluence of the Boyer South river is located on the northwest side of rang Sud-Ouest road, in Saint-Charles-de-Bellechasse. This confluence is located at west of the village of Saint-Gervais, south of the village of Saint-Charles-de-Bellechasse and east of the village of Saint-Henri.
The toponym Rivière Boyer Sud was formalized on December 5, 1968, at the Commission de toponymie du Québec.[2]