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 Fan Corn Du. It takes its name from a large coaching inn with a pitched slate roof (named after a local landowner, Storey Maskelyne), which was demolished in 1924. The site of the original inn is east of the centre, on the northeastern edge of the Pont ar Daf car park. Buses stop on either side of the A470 outside the centre. The car park at Pont ar Daf, from the Storey Arms centre, is the most popular access point for tourists and walkers to Pen y Fan. The car park, which has space for around 50 cars, is owned by