South River Nature Reserve protects four small parcels along South River, where the river meanders through the biologically rich lowlands of southern Antigonish County.

The reserve includes a mix of rich river floodplain and gentle forested slopes. It provides habitat for wood turtle, a listed species-at-risk. At least five at-risk plants occur here, including black ash.

The reserve protects the only provincial lands on South River in a landscape with much land use and disturbance of natural habitats. It is bounded by Dunmore Road along the western side and South River along the eastern side.