| Llancahue River | |
| Source1 Location: | Pellaifa Lake |
| Subdivision Type1: | Country |
| Subdivision Name1: | Chile |
| Mouth Elevation: | 209m (686feet) |
Llancahue River (Spanish: Río Llancahue)[1] is a river in Panguipulli commune, southern Chile. It drains Pellaifa Lake and flows westward into Calafquén Lake of which it is the primary source.