Tal-y-Llyn (also known as Llyn Mwyngil) is a very picturesque, mesotrophic lake lying just below Cadair Idris, which was formed when a huge landslip dammed the valley. It's approximately 220 acres in area, 1 mile long, about 10 feet deep and discharges into the river Dysynni. Parking can be found at lay-bys along the B4405 which runs along the south side, whilst a lane and footpath runs along the north side. Facilities at the southern end include a pub and an ice-cream shop. The north-western side is probably the best place for swimming, and the high mountains on either side provide good shelter from wind.