Cwm Llwch from Cwm Gwdi walk

Walking trail

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).

See the geological and archaeological features along the way

You will also take in the summit of Corn Du, the Tommy Jones obelisk and the legendary Llyn Cwm Llwch. Save this one for a clear day because then the views are truly spectacular.

Llyn Cwm Llwch with Pen-y-Fan and Corn Du in shadow, Brecon Beacons, Powys


Map route for Cwm Llwch horseshoe walk


Cwm Gwdi car park, grid ref: SO025248


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.


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.

Read more


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.

Read more


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.

Read more


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.

Read more


Continue along the tarmaced road until you reach a crossroads. Turn right and follow the road for ½ mile (800m) until you reach a right turn opposite Heolfanog cottage. Take the right turn and continue on the tarmac road for another ½ mile (800m) until you reach a sharp left. The entrance to Cwm Gwdi car park is on your right.


Cwm Gwdi car park, grid ref: SO025248

You made it

Following this trail on mobile or tablet? Share your experience.

Cwm Llwch from Cwm Gwdi walk


The route is on soil and hard stone-pitched paths in the mountains. There are several stiles to cross. The return route has some road sections, so please take care.

Dogs are welcome but must be on leads near livestock and on the road.

Cwm Llwch from Cwm Gwdi walk

Contact us

Cwm Llwch from Cwm Gwdi walk

How to get here

Cwm Gwdi, Brecon, Brecon Beacons
By train

Nearest station Merthyr Tydfil (20 miles/32 km).

By road

Access from the west end of Brecon along Newgate Street, turning up along Ffrwdgrech road 765yd (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 110yd (100m).

By bus

X43, Cardiff to Abergavenny passing through Brecon. Information at Traveline-Cymru

Cwm Llwch from Cwm Gwdi walk

Facilities and access

  • Dogs are welcome, please keep on leads near livestock and on the road