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All walksBrecon & the Usk Valley

Brecon & the Usk Valley

Pen y Fan from Cwm Gwdi

The long way up from the Brecon side, on the Cefn Cwm Llwch ridge. Twice the walk of the tourist path and a fraction of the people.

Distance
6.8 mi / 11 km
Time
4 hr
Ascent
650 m
Difficulty
Strenuous
Shape
There and back

Where it is

The circle shows the general area, not the exact start. Use the directions link below to get to the car park itself. Contours and paths shown are OpenTopoMap, drawn from OpenStreetMap data.

The route

From the old army camp, climb onto the Cefn Cwm Llwch ridge and follow it steadily south, with Llyn Cwm Llwch in its hollow to your right, all the way to the summit. Return the same way.

Worth knowing

  • This is the finest approach to the mountain and almost nobody uses it.
  • The ridge is narrow in places with big drops into the cwm. Not one for a windy day.
  • Allow four hours and treat it as a proper mountain day, not a stroll.

What you’ll see

Llyn Cwm Llwch far below, the north faces of Corn Du and Pen y Fan, and ravens working the crags.

Background

Llyn Cwm Llwch is a glacial tarn dammed by a moraine. Local legend held that an invisible island in the lake was the entrance to a fairy kingdom, accessible one day a year.