| Llyn Gwernan | |
| Pushpin Map: | Wales Gwynedd |
| Location: | Wales |
| Coords: | 52.7256°N -3.9214°W |
| Basin Countries: | United Kingdom |
| Area: | 3ha |
| Cities: | Dolgellau |
Llyn Gwernan is a lake in Gwynedd, Wales and an important geological site, notable for an unusual thickness of Devensian Late-glacial organic deposits.[1]