Llyn Cwm Llwch both Pen y Fan and Corn Du and indeed from the spur of Pen Milan to its west. Llyn Cwm Llwch Llyn Cwm Llwch () is a small lake or pool in the Brecon Beacons National Park in Powys, Wales. It is between 1 and 2 acres: much smaller than the two glacial lakes in the west of the Black Mountain (range): Llyn y Fan Fawr and Llyn y Fan Fach. It is of glacial origin, occupying a rock hollow beneath the peaks of Pen y Fan and Corn Du in the central Brecon Beacons. It is drained by the
Pen-y-ghent summit. The more direct route that traverses the southern 'nose' of the hill is the route usually taken by those attempting the Yorkshire Three Peaks Challenge, as the walk is usually (but not exclusively) done in an anti-clockwise direction starting and finishing in Horton in Ribblesdale. The other main hillwalking route on the hill heads north from the summit to reach Plover Hill before descending to join Foxup Road, a bridleway at the head of Littondale. Pen-y-ghent is one of the mountains on the Yorkshire Three Peaks route. Pen-y-Ghent is made up of a millstone grit top sat upon a