Llyn Trawsfynydd
General data
- Name: Llyn Trawsfynydd
- Water system: River Dwyryd
- Water type: Artificial lake
- Progression: Afon Prysor -> River Dwyryd -> Tremadog Bay -> Cardigan Bay -> Irish Sea -> Atlantic Ocean -> Planet Earth
- Climates: Temperate
- Continents: Europe
- Countries: Wales (UK)
Llyn Trawsfynydd is a large artificial reservoir situated near the village of Trawsfynydd in Gwynedd, North Wales. With a total surface area of 4.8 km2 (1,200 acres) the reservoir is slightly more extensive than Wales's largest natural lake, Bala Lake at 4.5 km2 (1,100 acres).