Cwm Llwch horseshoe walk

Cwm Gwdi, Brecon, Brecon Beacons

Route details and mapDownload as a print friendly PDF
Cribyn from Cefn Cwn Llwch path. © Paul Harris

Cribyn from Cefn Cwn Llwch path.

The Tommy Jones obelisk on the Brecon Beacons © National Trust

The Tommy Jones obelisk on the Brecon Beacons

Llyn Cwm Llwch © National Trust

Llyn Cwm Llwch

Route overview

This is the hard way to the summit of southern Britain's highest mountain, Pen y Fan. Starting at just over 1000ft (310m) above sea level you have 1893ft (576m) of climbing before the reaching the top at 2908ft (886m). You will also take in the summit of Corn Du, the Tommy Jones obelisk and the legendary Llyn Cwm Llwch. Weather permitting, the scenic views are truly something to behold, there’s also plenty of geological and archaeological features to see.

Route details

See this step-by-step route marked on a map

Cwm Llwch horseshoe trail map
  • Directions
  • Route
  • Bus stop
  • Parking
  • Toilet
  • Viewpoint

Start: Cwm Gwdi car park, grid ref: SO025248

  1. From the car park, take the tarmac road up to the gate and stile, then along the side of a field. In this area, among the prickly gorse you will find rifle and artillery abutments. These were used for military firing practice into the opposite hill of Alt Ddu.

  2. Step over the stile and slightly to your right there is a grassed track crossing several shallow grassed gullies, amongst the bracken heading up to a platform that once housed the quarry ponies. Keep right, close to the edge and follow the old pony and sledge track up past several small quarry sites. Take care, as there is still lots of loose stone lying about.

  3. Keep rising up and pass through a large quarry. Tile stones for roofs were cut from this quarry back in the 18th century. Once you reach the top, turn right and follow the obvious path along the ridge known as Cefn Cwm Llwch, all the way up to the summit of Pen y Fan. As you tackle the last very steep section on your left you can look down on the river of Nant Sere and across to the peak of Cribyn.


    This is the third highest peak in the Brecon Beacons. The path from the saddle between Pen y Fan and Cribyn has been stone pitched to reduce the effect of the hundreds of thousand of walkers that use the route each year.

    Cribyn from Cefn Cwn Llwch path. © Paul Harris
  4. Once you have taken a rest on the summit of Pen y Fan, follow the path down to the right and up to the summit of Corn Du, which stands at 2864ft (873m). From here find the steep path off the the north west end. Go down this and keep to the right, close to the edge of Cwm Llwch. Follow this path downhill to the obelisk of Tommy Jones.

    Show/HideTommy Jones Obelisk

    The obelisk is a monument to the tragic tale of a small boy called Tommy Jones who got lost and perished on the Brecon Beacons in 1900. A search by locals and soldiers carried on for 29 days before his body was found near the spot where the obelisk now stands.

    The Tommy Jones obelisk on the Brecon Beacons © National Trust
  5. From the obelisk, follow the path down and to the right to the lake known as Llyn Cwm Llwch. Turn left and continue to follow the path down crossing the stile and leaving National Trust land. Keep heading north, past a cottage and then a car park until you reach the tarmaced road.

    Show/HideLlyn Cwm Llwch

    This glacial lake was left behind when the glaciers that carved these mountains retreated at the end of the last Ice Age. There are many legends about the lake and fairies that live on an invisible island in the lake.

    Llyn Cwm Llwch © National Trust
  6. Continue along the tarmaced road until you reach a cross roads, Turn right and follow the road for half a mile (850m) until you reach a right turn opposite Heolfanog cottage. Take the right turn and continue on the tarmac road for another half mile (850m) until you reach a sharp left. The entrance to Cwm Gwdi car park is on your right.

End: Cwm Gwdi car park, grid ref: SO025248

  • Trail: Walking
  • Grade: Hard
  • Distance: 8 miles (12.8km)
  • Time: 5 hours
  • OS Map: Landranger 160; Explorer OL12
  • Terrain:

    The route is on soil and hard stone paths in the mountains. There are several stiles to cross. The return route has some road sections, so care must be taken. Dogs are welcome but must be on leads near livestock and on the road.

  • How to get here:

    By bus: X43, Cardiff to Abergavenny passing through Brecon. Information Traveline-cymru

    By train: Nearest station Merthyr Tydfil (20 miles/32 km)

    By car: Access from the west end of Brecon along Newgate Street, turning up along Ffrwdgrech road 765yds (700m). At three fork roads, take the far left and follow road up to crossroads for 1.5 miles (2.4km). Travel ahead, over cattle grid with National Trust sign and continue up to car park 110yds (100m)

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