The crest of Y Grib

A strenuous and airy climb on to the Black Mountains via one of the Beacons' finest ridges.


Y Grib


7.25 miles (11.7kms)

1906ft (581m)
4hrs 30min

About the walk

This is the classic climb on to the highest ground of the Black Mountains. The steep western slopes of the towering massif, accentuated by a succession of grassy arêtes and rounded promontories, hide a multitude of remote cwms that rarely reveal their splendour to the walker.

Y Grib

From the airy ramparts of Castell Dinas, the full length of the bold escarpment unfolds and, while many paths breach its defences, none do so in quite such a dramatic fashion as the one that traces the slender crest of Y Grib. Compared to the gentle standards of this normally rounded and uniform landscape, this narrow grassy walkway feels almost knife-edge in places. Once up, you'll make easy progress through the eroded peat of Pen y Manllwyn and across the top of the boggy plateau to the massif's high point of Waun Fach.

Waun Fach

The line of descent harbours its own treasures as it follows the narrow spur of Pen Trumau, which sweeps gracefully around a deep chasm formed by the infant Grwyne Fechan river. Huge views across the valley show the formidable bulk of Waun Fach as it would want to be seen; the usually understated summit transforms itself into an impressive towering giant that stands head and shoulders above the line of pretenders to its grassy crown. A rocky saddle, steeped in the atmosphere of the craggy peaks that surround it, marks the last of the high mountain scenery.

A basic windbreak offers shelter from the cruel wind that often sweeps through the pass and also affords fine views over the expansive Grwyne Fechan Valley. The route is for more experienced walkers, and should be not attempted in poor weather or when visibility is reduced.

Walk directions

A set of wooden steps go down from the back of the car park on the eastern side of the road. These lead on to a rough track where you turn right and then, after 30yds (27m), left over a stile. Follow the permissive path down the side of the wood to a stream, cross a stile and then cross the stream.

Keep to the left edge of the field, with trees on your left, and climb steeply to the top of the field. Leave the wood behind and follow the fence line upwards to another stile. This leads on to the flanks of Castell Dinas.

Keep straight ahead here to cross the ruins and descend steeply into a deep saddle. Cross a stile and a broad track, then climb directly up the steep spur ahead. You're now on Y Grib and it's possible to follow the faint track all the way up to a cairn and then down to a small notch where your route is crossed by a bridleway.

Climb steeply back out of this and hug the crest up to another cairn. Now keep ahead on a fainter path that passes another cairn before climbing steeply, straight ahead, on to the broad spur of Pen y Manllwyn.

Here, at a tiny cairn, turn right on to a clear track that leads over the top of Pen y Manllwyn (marked by a cairn) and up to the boggy plateau on top of Waun Fach. The summit is stranded in a puddle of wet peat that makes it an undesirable picnic spot. Turn right and follow the obvious path down on to the evernarrowing spur of Pen Trumau.

Cross the narrow summit and, as the ground steepens, follow the path through rocky outcrops to a broad saddle, marked by a large cairn. Turn sharp right here and follow the main track as it descends, easily at first. This steepens and becomes rocky for a while, going through several gates, before it reaches a gate above a walled track.

Follow the track down to the road and turn right, then immediately left. Drop to the bottom of the valley past Cwmfforest Riding Centre and climb out again on the other side. As the road turns sharply to the left, bear right on to a stony farm track that runs between hedgerows. Follow this track until it turns sharply left where you continue straight ahead along a narrower track between hedges. This will take you past the stile you crossed earlier, on the right-hand side, then take the steps on your left, back to the car park.

Additional information

Clear tracks over farmland, rolling moorland and narrow ridge, quiet lane, several stiles

High mountain plateau, narrow ridge, steep grassy escarpment, deep and remote cwms

Care needed near livestock

AA Walker's Map 17 Brecon & The Black Mountains

Castle Inn, Pengenffordd, allows parking for small fee

None on route

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Walking in safety

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About the area

Discover Powys

The largest unitary authority in Wales, Powys covers an area of approximately 2,000 square miles. Much of that is mountainous because it actually has the lowest population density of all the Welsh counties.

This much wild, empty space is perhaps best typified by the International Dark Sky Reserve in the Brecon Beacons National Park, one of only eleven in the world. The absence of light pollution creates an exceptional spot for star gazing. You won’t find any cities in Powys, just villages and smaller-sized towns, but that’s the way its inhabitants like it. 

Newtown, the largest settlement, is perhaps most famous for being the birthplace of Robert Owen, the founder of the Co-operative movement. Brecon is a market town set on the edge of the Brecon Beacons National Park, while the pretty Victorian spa town of Llandrindod Wells boasts the National Cycle Collection. Elsewhere, Hay-on-Wye hosts a major literary festival every year.

Powys is liberally scattered with castles, burial mounds, hill forts, and other historic markers; Powis Castle, near Welshpool is probably one of the most impressive. And for walking enthusiasts, it’s not just the Brecon Beacons on offer – the Elan Valley describes itself as the ‘Welsh Lake District’.