Pen y Fan (pronounced /pɛn.ə.ˈvan/) is the highest peak in South Wales and southern Britain, situated in the Brecon Beacons National Park. At 886 metres (2,907 ft) above sea-level, it is also the highest peak in Britain south of the Snowdonia mountain range. The twin summits of Pen y Fan and Corn Du were formerly referred to as Cadair Arthur or 'Arthur's Seat'.
The summit lies on a ridge stretching from Talybont Reservoir in the east, to the A470. 500 m (1,600 ft) west lies the subsidiary top of Corn Du, beyond which the terrain drops at a moderate angle to the subsidiary top of Y Gyrn then more steeply to the Storey Arms on the A470. To the east, the ridge drops steeply to the col connecting it to Cribyn, the next mountain along the ridge. From Corn Du, a gentle ridge descends south towards Merthyr Tydfil.
The mountain and surrounding area are owned by the National Trust whose work parties attempt to combat the erosion caused by the passage of thousands of feet up and down this most popular of South Wales' peaks. The mountain is used by the military as part of the selection process of the UK's Special Forces personnel. (See "Fan Dance").
The Brecon Beacons (Welsh: Bannau Brycheiniog) is a mountain range in South Wales. In a narrow sense, the name refers to the range of Old Red Sandstone peaks popular with walkers which lie to the south of Brecon. Sometimes referred to as "the central Beacons" they include South Wales' highest mountain, Pen y Fan. The range forms the central section of the Brecon Beacons National Park (Parc Cenedlaethol Bannau Brycheiniog), a designation which also encompasses ranges both to the east and the west of "the central Beacons". This much wider area is also commonly referred to as "the Brecon Beacons".