SO2129 : Llwybr Waun Fach / Waun Fach Path
Strenuous; exposed mountain ridges

Waun Fach

811m Elevation
622m Prominence
Wales Country
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SO2129 : Llwybr Waun Fach / Waun Fach Path

Alan Richards Photo source

Overview

Waun Fach is the 811 m high point of the Black Mountains in the eastern Bannau Brycheiniog National Park. Its broad, peaty summit contrasts with the steeper ridges below. The western circuit from Pengenffordd follows Y Grib, known as the Dragon’s Back; a separate approach from the Grwyne Fawr valley links Waun Fach with Pen y Gadair Fawr. Restored upland paths protect fragile peat, but these remain exposed mountain walks.

Waun Fach

Waun Fach rises to 811 m in Powys and is the highest point of the eastern Black Mountains. It is separate from the western Black Mountain range and from the individual summit called Black Mountain near the English border.

Summit and terrain

The recorded high ground is featureless, 20 m northeast of an OS bolt in a concrete block. Do not look for a prominent intact trig pillar. The summit is broad and peaty, with restored paths across parts of the upland. Pen y Gadair Fawr, 800 m, is the distinct neighbouring top to the southeast.

Complete walks

The western circuit begins and ends at Pengenffordd. It climbs over Castell Dinas and Y Grib, the Dragon’s Back, before reaching Waun Fach via Pen y Manllwyn. The return descends Pen Trumau and uses the lower tracks and lanes past Cwmfforest. The AA describes this complete castle circuit as 12.9 km and about four and a half hours. Other published Dragon’s Back variants use different alignments.

A separate circuit begins and ends at Mynydd Du/Blaen-y-Cwm car park. It reaches the western ridge and Pen y Gadair Fawr, continues to Waun Fach, then returns through the upper Grwyne Fawr valley past the reservoir and dam. Plan the full route carefully through the forest and open uplands. The reservoir-only walk and the circuit over Rhos Dirion do not automatically visit Waun Fach.

Safety and access

These are exposed mountain outings. Strong wind, low cloud, slippery steep ground and winter ice can make them demanding. Carry suitable clothing, food, water and navigation equipment, and be able to navigate without a phone signal. Y Grib and Pen Trumau have steeper and narrower sections; allow enough daylight for the entire return.

Keep to repaired paths to protect the peat, and follow restoration and forestry work signs. Do not treat every mapped forest track as open or usable. Keep dogs controlled around livestock and take care on the lower lanes. Path improvement does not remove mountain-weather risks.

Getting there

Use designated walkers’ parking by the Dinas Castle Inn on the A479 at Pengenffordd, following current signs and charges. The alternative Mynydd Du/Blaen-y-Cwm car park is at SO253285 and is approached by narrow valley lanes. Abergavenny is the main rail gateway; arrange onward travel and the return connection for the chosen trailhead. Talgarth and Crickhowell provide supplies. Check pub and toilet opening arrangements and carry your own essentials.

Landscape, name and history

Waun Fach means small or little moorland in Welsh. The mountain belongs to the Lower Devonian Old Red Sandstone landscape, dominated by sandstone with mudstone interbeds. Erosion creates stepped slopes, and glaciation shaped the surrounding valleys. In clear weather the ridges overlook the Black Mountains, Wye Valley and central Bannau Brycheiniog.

Castell Dinas preserves a medieval castle over an Iron Age enclosure. Modern conservation on Waun Fach focuses on repairing eroded paths and restoring peatland. Stay on established routes so recovering ground is not trampled.

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Route planning notes

These notes describe possible approaches. Check a route's map and access information when planning your walk.

Pengenffordd, Castell Dinas and Dragon’s Back circuit

From the walkers’ car park by the Dinas Castle Inn, climb through the fields to Castell Dinas, then follow Y Grib to Pen y Manllwyn and Waun Fach. Descend southwest over Pen Trumau to the saddle and take the western track down to the lanes. Return past Cwmfforest and along the hedge-lined track to the same car park. The AA’s full castle circuit is 12.9 km, with a published estimate of four and a half hours; allow longer for slower conditions. It includes steep ridge sections, stiles and road walking.

12.9 km Strenuous

Mynydd Du, Pen y Gadair Fawr and reservoir circuit

Start and finish at Mynydd Du/Blaen-y-Cwm car park in the Grwyne Fawr valley. Climb the western side of the valley to the ridge and Pen y Gadair Fawr, then follow the upland path northwest to Waun Fach. Continue to the head of the Grwyne Fawr valley and descend past the reservoir and dam, returning by the valley track to the car park. This remote circuit needs a detailed map, careful choices at forestry junctions and attention to current work signs. The reservoir-only walk and the Rhos Dirion circuit follow different itineraries.

Strenuous; remote mountain circuit
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Hill facts and local notes

Classifications

Marilyn Simm Hewitt Nuttall

Elevation

811m

2,661 ft

Prominence

622m

Coordinates

51.9628, -3.1432

SO215299

OS Map

161

Explorer: OL13N

At the Summit

The highest ground has no distinctive feature. DoBIH places it 20 m northeast of an OS bolt in a concrete block, at SO 21552 29989. The concrete block is a nearby reference point, rather than the highest ground on the broad summit plateau.

Terrain & Geology

Restored stone-surfaced upland paths broad peat moorland boggy and eroded ground off the paths steep grassy and rocky ridges farmland tracks stiles and lanes on the Pengenffordd circuit forestry tracks and rough valley paths on eastern approaches

Waun Fach belongs to the Old Red Sandstone landscape of the Black Mountains. Lower Devonian river-deposited sandstones of the Brownstones and Senni formations dominate the uplands, with mudstone layers between them. Differential erosion helps produce the stepped valley sides. Glaciers shaped the surrounding valleys, while peat covers much of the broad summit area.

Views & Scenery

In clear weather, the open ridges give wide views across the Black Mountains, towards the Wye Valley and west towards the central Bannau Brycheiniog, including Pen y Fan. Pen y Gadair Fawr is the more pointed neighbouring summit to the southeast.

History & Heritage

Name Origin

The name 'Waun Fach' is derived from Welsh, meaning 'small moorland', a fitting description given its character.

Historical Significance

The western circuit crosses Castell Dinas, where a medieval masonry castle occupies an earlier Iron Age enclosure above the Rhiangoll pass. On Waun Fach itself, modern path repairs and peatland restoration aim to reduce erosion and help damaged bog recover.

Getting There & Facilities

Parking

For the western circuit, use the designated walkers’ parking by the Dinas Castle Inn at Pengenffordd on the A479. Follow the current parking signs and payment instructions; do not assume the pub’s guest parking is available. For the eastern valley approach, use Mynydd Du/Blaen-y-Cwm car park at SO253285, reached along narrow lanes through the Grwyne Fawr valley. Keep gates, entrances and passing places clear.

Public Transport

Abergavenny is the main rail gateway. Plan onward travel to Talgarth or Crickhowell and the chosen trailhead using current Traveline Cymru information. Confirm the return connection before starting; reaching a nearby town does not put you at the Pengenffordd or Mynydd Du car park.

Nearby Facilities

There are no summit facilities or toilets on the western mountain circuit. The Dinas Castle Inn at Pengenffordd offers refreshments when open, with more supplies in Talgarth and Crickhowell. Check opening and toilet arrangements before relying on them, and carry food and water for the complete walk.

Safety Information

Known Hazards

  • The plateau and ridges are exposed to strong wind, low cloud and rapid weather changes. Carry a map and compass and know how to use them; identify the correct descent before leaving the summit.
  • Y Grib and Pen Trumau include steep, narrower grassy or rocky sections. Wet ground can be slippery, and the western circuit needs confident footing. Avoid committing to exposed ridges in unsuitable weather.
  • Peat beside the repaired paths is fragile and can be very wet or eroded. Stay on the established surface and respect restoration areas, barriers and any temporary work signs.
  • The Grwyne Fawr approach is remote and includes forestry junctions and rough tracks. Forest routes can change with management work; follow current notices and do not enter closed working areas.
  • The lower western circuit crosses farmland, stiles and lanes. Keep dogs controlled around livestock, leave gates as found and take care near roads and farm traffic.

Seasonal Hazards

Snow and ice can make the steep ridge sections substantially harder, and short winter days leave less margin for a long circuit. Wet weather increases bogginess and slippery footing. Check the mountain forecast, daylight and current access notices before setting out; carry warm layers and waterproofs in every season.

General Safety Tips

  • Check weather conditions before setting out
  • Carry appropriate clothing and equipment
  • Let someone know your planned route
  • Take a map, compass, and GPS device
  • Carry emergency supplies: food, water, first aid kit, torch

Hills

Some common questions about the hills answered

Are there group walks up Waun Fach?

Many walkers use Walkmates to join or organise walks with others. You can check for group walks around Waun Fach through the maps

Are there other walkers around Waun Fach?

Activity varies by location and time, but Walkmates lets you see whether others have shared walks or shown interest in this area. Find other people through the walking friends search walking friends for Waun Fach search or of course create your own walk for Waun Fach

Can I organise a walk to Waun Fach?

Yes. If there aren’t any walks listed already, you can create a walk and make it available for others to join.

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How do I find a walk up this hill?

There are often multiple ways to walk this hill, depending on experience and route preference. Walkmates helps you explore walks and routes that others have shared.

Can I suggest a new route up Waun Fach?

Yes. You can suggest or create routes to share with others. Walkmates focuses on the social side of walking, so routes are used to help people organise walks and explore areas together, rather than as detailed navigation tools or route libraries.

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Location

Waun Fach location map

Grid reference: SO215299

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