Pen y Fan () is the highest peak in south Wales, situated in the Brecon Beacons National Park. At 886 metres (2,907 ft) above sea-level, it is also the highest British peak south of Cadair Idris in Snowdonia. The twin summits of Pen y Fan and Corn Du at 873 m (2,864 ft) were formerly referred to as Cadair Arthur or 'Arthur's Seat'.