A difficult route in Black Mountains. Check the GPS track on Outdooractive for full details of the route, waypoints, and terrain.
Starting Point: Large layby on the A479, Pengenffordd (SO 173 296)
Terrain: Field path, woodland edge, open hillside, Castell Dinas, rocky descent, valley track, lane, open moorland, indistinct path, cairn, Cambrian Way, open mountain, summit plateau, Cambrian Way return, Y Grib ridge, Castell Dinas retrace Notable features: A479 layby, Castell Dinas (highest castle in England and Wales, 450m), Y Grib ridge, Rhiangoll valley, Waun Fach (811m — highest point in the Black Mountains), Cambrian Way, Pen Trumau, cairns, Rhiw Trumau NAVIGATION WARNING: The path across the lower moorland south of SO 195 300 is indistinct and easy to lose. The ground between SO 195 300 and the cairn at SO 199 290 requires careful navigation — the path bears progressively southeast across featureless terrain. Use a compass bearing if in doubt and aim for the cairn. This section was walked with repeated loss and recovery of the path. TERRAIN WARNING: Waun Fach and the surrounding Black Mountains plateau can be exposed and boggy in wet conditions. The summit area in particular holds water. Appropriate footwear and clothing are essential regardless of conditions in the valley.
A superb and varied mountain day in the heart of the Black Mountains, combining one of the oldest and most dramatically positioned historical sites in Wales with the highest summit in the range and one of its finest ridge walks. The ascent to Castell Dinas sets an immediate tone — the Norman remains and Iron Age earthworks at 450 metres command the Rhiangoll pass in a way that must have been as formidable a thousand years ago as it looks today. The valley section below Y Grib is pleasant and unhurried, and the climb south onto the Waun Fach plateau, while navigationally demanding on indistinct ground, has a real sense of wilderness about it that the more frequented Beacons walks rarely match. The summit of Waun Fach — broad, grassy and genuinely high at 811 metres — delivers views that justify every step of the ascent. The return north on the Cambrian Way and then southeast along the Y Grib ridge is the walk's finest hour: a clear, narrow crest with the Rhiangoll valley falling away to the right and the Black Mountains plateau stretching to the left, the kind of ridge that keeps walkers coming back to these hills.