Hay Bluff

Hay Bluff (Welsh: Penybegwn) is a prominent hill at the northern tip of the Black Mountains, an extensive upland massif which straddles the border between south-east Wales and England. Its flat summit which overlooks the middle Wye Valley and the book town of Hay-on-Wye is marked by a triangulation pillar at a height of 677 metres (2,221 ft).

The hill is largely within the Welsh county of Powys though parts of its eastern flanks lie within the English county of Herefordshire.

Geology

The base and indeed greater part of the hill is formed from mudstones of the St Maughans Formation whilst the upper part is formed from the sandstones and mudstones of the Senni Beds Formation, both of which are assigned to the Old Red Sandstone laid down during the Devonian period. A number of small quarries have been worked on its slopes in the past, not least for the Ffynnon Limestone, a calcrete which crops out along the northeastern and northwestern flanks of the hill at the base of the Senni Beds.

Access

The Offa's Dyke national trail makes a steep ascent of the hill's northern slopes and then heads southeastwards along the broad ridge of the Black Mountain. A more gentle path to the summit follows the crest of the north-facing scarp, known as Ffynnon y Parc, from the road summit 1 mile to the southwest at Gospel Pass. The entire hill is designated as open country thus providing walkers with the freedom to roam at will.