Merthyr Tydfil waterfall walk

Including Pwll Annie and Cyfarthfa Pwll Glas.

Ability requirements (key)


From Cardiff, take the A470 to Merthyr Tydfil. For the Pwll Annie main waterfall, take the A465 to the left, and shortly after passing over the first bridge, park on the verge on the left. SO 0230 0742. For the lower Pwll Annie waterfall and Cyfarthfa Pwll Glas, take the A4102 to the right, past one more roundabout, and turn left at the traffic lights, onto the A4054. Turn left at the mini roundabout in front of the Cyfarthfa Castle gates. Continue past the next mini-roundabout, then immediately after a pedestrian crossing and immediately before The Lord Raglan pub, turn left at a crossroads into Old Chapel Road. Stay with it as it swings right and passes under the Cefn Coed Viaduct. Park on the roadside just after it crosses the Taff river. SO 0294 0773.


Warning: The main Pwll Annie waterfall is situated in a very difficult location, and should only be accessed by very experienced (expert) visitors, who are very confident with their abilities around the potentially lethal crags. The crags prevent easy access from any direction, and a fall from them will certainly result in serious injury, if not death. Treat this site with extreme caution. The lower waterfall and Cyfarthfa Pwll Glas can be accessed with comparatively little difficulty, though care must still be taken in the gorge.

Pwll Annie main waterfall

For the Pwll Annie main waterfall, start at the verge on the A465. Head down the hill to the bridge over the Nant Ffrwd gorge, and cross to the left side of the bridge (when looking downhill). At the lower end of the bridge, carefully cross the fence into the fields (you should ask for permission from the landowner), and proceed away from the road, along the edge of the gorge. About 20 or 30 metres before the waterfall, locate somewhere safe enough to descend into the upper gorge, taking great care to avoid the crags, and the final few metres which are vertical at all points. With luck, a fallen tree or fallen rock may aid the final part of the descent. Do not attempt to descend the lower waterfall from here.

Lower Pwll Annie waterfall and Cyfarthfa Pwll Glas

For the lower Pwll Annie waterfall and Cyfarthfa Pwll Glas, start at the parking spot under the Cefn Coed Viaduct. Head away from the river, taking the left track that almost immediately splits off from the lane. When it crosses a stream, follow it upstream for 500 metres to reach the gorge under the A465 bridge, with the lower Pwll Annie waterfall at its head. Watch out for falling debris while in the gorge, and note that there is no official path anywhere along the stream.

Return to the track and continue beyond the stream, then just before it passes under the A470 bridge, take a small path to the left that climbs up to the Taff Trail which runs on top of the viaduct. Follow it ahead-right (away from the viaduct) for about 800 metres, to Pont y Cafnau - the World's oldest surviving iron railway bridge (1793) - which leads off on the left into the Cyfarthfa Industrial Estate. Follow the estate road to the left, and just as you reach the other end of the industrial estate, drop down the river bank on the left to see the Cyfarthfa Pwll Glas waterfall, which lies immediately upstream. The view may be obscured by leaves in summer.

For added interest, continue a short distance along the Taff Trail past Pont y Cafnau, to reach the Cyfarthfa Ironworks.

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More about this area

Whilst every care has been taken in the compilation of this description, neither the author nor his fellow walkers can accept responsibility for loss or injury arising from any errors, omissions or inaccuracies in this description. This description is intended as a guide only, and you should select a route to suit your own abilities, at your own discretion. Ability requirements are a guide only. Route maps are approximated. You follow this description at your own risk.