�� Llyn Cwellyn

Llyn Cwellyn is a reservoir in North Wales which supplies drinking water to parts of Gwynedd and Anglesey. It lies on Afon Gwyrfai in Nant y Betws between Moel Eilio and Mynydd Mawr in the northern part of Snowdonia National Park. It has an area of 215 acres (0.87 km2), and is over 120 ft (37 m) deep. It is considered relatively oligotrophic. At the southern end is the small village of Rhyd Ddu.