Black Mountain Range To the western area of the Brecon Beacons National Park lies the Black Mountain Range. The heighest peak within the range is Fan Brycheiniog (802m). Llyn Fan y Fawr and Llyn Fan y Fach are lakes formed from glacial movement during the ice ages. The shape of the landscape is truly breath taking with its escarpments, lakes and cwms (amphitheatre like valleys). Picws Du (749 metres), Fan Foel and Fan Hir (761 metres) are popular with walkers as it forms a ridge along side the lakes. In the far western area of the Black Mountain Range lies Tair Carn Uchaf (482m) which has a huge cairn at the summit (one of three cairns which gives the peak its name). Gareg Lwyd is a subsidary summit of Fan Brychenioig at 616m it has no footpath to access the summit, but can be reached from the A4069 mountain road. It has a dry stone built OS triangulation pillar at the summit and a large cairn.