Llyn Llywenan
General data
- Name: Llyn Llywenan
- Water system: Planet Earth
- Water type: Natural lake
- Progression: Planet Earth
- Climates: Temperate
- Continents: Europe
- Countries: Wales (UK)
Llyn Llywenan (Welsh for 'Yew tree lake') is a lake in western Anglesey, Wales found just over 1 kilometre (0.6 mi) north of the village of Bodedern and 9 kilometres (5.6 mi) east of the town of Holyhead. At a maximum length of 1.1 kilometres (0.7 mi) and breadth of 0.4 kilometres (0.2 mi) it has a surface area of only 0.4 square kilometres (0.2 sq mi). This makes it the largest natural lake on the island—both Llyn Alaw and Llyn Cefni are larger but are man made.