Trail Running > Routes > Brecon Beacons Routes > Cribarth & Carreg Goch
An adventurous 16 km fell run through the Brecon Beacons’ wild limestone country, rich in geology and industrial history.
Why run this trail?
This compact but demanding fell run explores the wild uplands above the Tawe Valley, linking the remote summits of Disgwylfa, Carreg Goch and Cribarth across one of the Brecon Beacons’ most distinctive landscapes.
Renowned for its natural limestone geology and the striking post-industrial landscape of Cribarth, the route demands constant focus. Rocky escarpments, sprawling quarry workings and broken ground make for engaging mountain running that rewards confident navigation and strong ankles.
In return, you’ll have one of the quieter corners of the Brecon Beacons almost entirely to yourself, with expansive views across the Black Mountain ridge, the broad uplands of Fforest Fawr and the Swansea Valley stretching south towards the coast.
The traverse around Disgwylfa and Sinc Giedd is best reserved for clear weather and a prolonged spell of dry conditions. This section is pathless, with shake holes, extensive boulder fields, dense vegetation and hidden bogs that require constant awareness.
If you’re looking for a route that feels genuinely adventurous rather than simply hard, this is one of the Brecon Beacons’ finest hidden challenges.
Craig y Nos to Twyn Spratt
The run starts from the impressively situated Craig-y-Nos Country Park on the A4067 (parking is £3, all day). Head down through the main gate and cross the River Tawe, bearing left on a wide, accessible path through the park. It’s an easy start following the banks of the river, with the impressive crags of Penwyllt dominating overhead.
Take the boardwalks around a duck pond to emerge onto the A4067, then cross the road and pass over a stile into a large field that features a modern stone circle. There’s some great views across to Cribarth on your left as you climb gradually up to the National Showcaves Centre.
Turn right at the coach park and continue through the campsite. After about 300 m, follow the footpath sign on the left into trees. Turn left through the gate at the top and follow the track out onto the fell. It’s worth pausing your climb and looking back for impressive views across to the shapely peak of Fan Gyhirych and the Fforest Fawr skyline.
The bridleway soon swings right and the landscape opens out – a large expanse of undulating rough moorland dotted with rocky outcrops and boulder fields, with the occasional hawthorn offering a lonely silhouette against the skyline.
Twyn Spratt to Disgwylfa
Follow the bridleway as it climbs and twists its way across the moor. The area is pockmarked with shake holes – a natural phenomenon caused by erosion of the limestone into the extensive cave system below. It’s a beautifully desolate setting, the solitude heightened by the imposing ridge of Fan Hir and Fan Brycheiniog dominating the view ahead.
You’ll see the high point of Disgwylfa (544 m) clearly from the track, though to reach it in a direct fashion you’ll need to pick up a series of faint trods (at best) through the boulders, coarse grass and bilberry towards the rocky outcrops and strata which form its ‘summit’.
The effort is rewarded at the top with sweeping views of the entire Black Mountain ridge – from Garreg Lwyd in the west to Fan Hir in the east and the large basin of wilderness directly below you: snaking channels carved by the rivers Giedd and Haffes and the large expanse of the great bog Waun Fignen Felen. It’s no exaggeration to say that grazing sheep are the only visible sign of human intervention for as far as the eye can see.
Disgwylfa to MF509 Crash Site
The simplest route off Disgwylfa is to head directly south on faint tracks towards Carreg Goch. This is definitely the safest option if conditions are poor or you just want to keep it simple.
I tackled this route after a summer of consecutive heatwaves, so opted to drop down the western slope towards Afon Giedd and follow the valley along to Sinc Giedd – where the river (which was dry during my visit) disappears underground through a sink hole at the end of the valley.
It’s worth pointing out that this entire section is pathless and littered with natural obstacles, gradients and hazards that require a slow and steady approach that’s not entirely conducive to running. I’d definitely classify this leg of the route as exploring with intent.
The payoffs are some impressive landscape features and a striking remoteness, but it does require continual route assessment and a ready supply of physical and mental stamina. After picking my way down the valley for about 1 km, I skirted the lip of some large peat hags and began the ascent of Carreg Goch.
There are some prominent rock pavements heading uphill at a comfortably steep gradient which I treated as ladders – much quicker than the prevailing broken landscape around me and with the inbuilt bonus of a clear directional pull towards the summit.
You’ll soon join a clear, grassy track that intersects your climb. Bear right and it’s a short jog to reach the Wellington Bomber (MF509) crash site at SN 81613 16919.
Marked by a lone Canadian flag fluttering in the breeze and a small stone memorial, a surprisingly intact tangle of wreckage marks the site of this tragic air crash that cost the lives of six Canadian airmen in 1944. It’s an atmospheric place to pause and get your bearings before tackling the remaining climb to Carreg Goch.
MF509 Crash Site to Carreg Goch
There are no direct tracks to the summit of Carreg Goch (558 m) from the crash site marked on OS Maps and no clearly discernible ones on the ground. My route climbs directly west from the crash site and then swings north to the top, switching between grass, one or two faint trods and more rock pavements.
Carreg Goch is a slightly gentler proposition than Disgwylfa and sees marginally more foot traffic, though there’s little to distinguish it as a true summit except a perceptibly higher vantage point.
By this stage of the run you may have become accustomed to the views, but this elevated position at the heart of the plateau offers a real sense of space, with sweeping panoramas in every direction.
Carreg Goch to Pwll-yr-Cawr
The descent from Carreg Goch is fairly straightforward, with visible grassy tracks weaving around rocky outcrops, shake holes and ponds of varying size. It’s a welcome return to faster, simpler running after the slow, deliberate route-finding higher up the plateau.
You’ll eventually reach a fenced enclosure with a stile by a huge erratic. Ignore the stile and bear left to skirt the enclosure and continue descending through reedy vegetation and richer grassland.
You’ll soon arrive at the enormous sink hole of Pwll-yr-Cawr (Pit of the Giant). Measuring around 30 m deep and 100 m across, it’s impossible to miss, no matter how much your attention has drifted towards the looming outline of Cribarth ahead.
Pwll-yr-Cawr to Cribarth
Skirt the edge of the sink hole and follow the track around to the right, passing through tall reeds and bracken. You’ll suddenly encounter the standing stones of Saith Maen (Seven Stones).
This must be particularly rich grazing land as the sheep surrounding me were only slightly more interested in moving out of my way than the stones, which have stood still for about 4,000 years.
From the stones, it’s about 2 km of steady climbing on clear tracks to reach the trig point on Cribarth. It’s all relative, of course, and with two days of running in my legs and some testing off-piste chicanery in the preceding 10 km to get this far, it seemed to inch closer at a painfully slow rate.
Cribarth (423 m) may easily be perceived as a natural, craggy summit from the valley floor, but this is an illusion. Up close, the hill is a complex structure of quarry workings, old tram roads and exposed crags that present plenty of exploratory possibilities on the ground.
From the trig point, the view north over the plateau you’ve just traversed puts everything into context, while the birds-eye view of the Tawe Valley to the southeast provides an immediate counterpoint: human activity and civilisation.
Cribarth to Craig-y-Nos
Once you’re done with the trig point, head northeast towards the tilted strata of impressive crags on Cribarth. If there’s anything left in the legs there are some great steep ramps and dramatic viewpoints to explore.
Follow your nose until the crags diminish and the track descends towards a drystone wall at an obvious corner. Turn right and then left over a stile to descend on a very steep track on the edge of scrubby woodland. This gradually levels off, curving sharply back through the trees to emerge by a gate on the A4067.
Turn left for the final 400 m on the pavement back to Craig-y-Nos Country Park where there are great facilities for a freshen up and a well-earned bite to eat. After a route that demands stamina, concentration and curiosity in equal measure, it makes a very civilised place to unwind and reflect on a truly special running adventure.
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Have you run this route? If you’ve discovered a better variation, noticed something that’s changed or have local knowledge to share, I’d love to hear from you.
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Trail Running Routes in the Brecon Beacons
Disclaimer
All routes and GPX files are provided as a guide only. Conditions, rights of way, and landmarks may change. Always carry an up‑to‑date map and use your own judgement. See the Trail Run Disclaimer page for details.