| South River | |
| Pushpin Map: | Maine#New Hampshire#USA |
| Pushpin Map Size: | 250 px |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | States |
| Subdivision Name2: | New Hampshire, Maine |
| Subdivision Type3: | Counties |
| Subdivision Name3: | Carroll, NH, York, ME |
| Subdivision Type4: | Towns |
| Subdivision Name4: | Effingham, NH, Parsonsfield, ME |
| Length: | 10.6miles |
| Source1: | Province Lake |
| Source1 Location: | Effingham, NH |
| Source1 Coordinates: | 43.7°N -70.9972°W |
| Source1 Elevation: | 480feet |
| Mouth: | Ossipee River |
| Mouth Location: | Parsonsfield, ME |
| Mouth Coordinates: | 43.7847°N -70.9567°W |
| Mouth Elevation: | 375feet |
| Tributaries Left: | Salmon Brook, Hobbs Brook |
| Tributaries Right: | Emerson Brook |
The South River is a 10.6adj=midNaNadj=mid[1] river in eastern New Hampshire and western Maine in the United States. It is a tributary of the Ossipee River, which flows east to the Saco River and ultimately the Atlantic Ocean.
The South River begins at the outlet of Province Lake in the town of Effingham, New Hampshire, and proceeds north past the village of Center Effingham. Jogging east, the river enters Parsonsfield, Maine, then turns north again to reach the Ossipee River.