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
Chwarel y Fan Chwarel y Fan Chwarel y Fan is a peak in the Black Mountains in south-eastern Wales. It is the highest rise on the long ridge which extends southeastwards from Rhos Dirion. The ridge continues southeastwards to the lesser summit of Bal-Mawr whose top is adorned by a trig point at above sea level. A further 1 km southeast along the ridge is the lesser top of Bal-Bach at a height of just over . Chwarel y Fan is the county top of the historic county of Monmouthshire, and is also the highest point in the current local government area of