Pen y Fan Pen y Fan Pen y Fan () is the highest peak in south Wales, situated in the Brecon Beacons National Park. At 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'. 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
Pen-y-fan Pond Pen-y-fan Pond Pen-y-fan Pond is a man-made reservoir built around 1794-6 as part of the engineering works for the Crumlin Arm of the Monmouthshire Canal. The reservoir was used to maintain the water level in the canal. The reservoir is formed by a large earth dam with stone facings, forming banks on three sides of a gentle slope. The outlet to the canal feeder forms a stone-lined, oval tunnel and a valve chamber is set into the bank above. Pen Y Fan Pond Country Park features the reservoir, and provides a circular walk around the lake, and minimal facilities for