Including Berw Nant yr Ychen, Pen Pych waterfall/Berw Wion, Nant Melyn Waterfall, Nant Carnfoesen Waterfall, Rhondda Fawr Waterfall.
From Cardiff, take the A470 to the end of Merthyr Tydfil. From Merthyr Tydfil, take the A465 to Hirwaun, follow it over the hill, and down to the next roundabout. Take second exit to the next roundabout. Take the first exit and continue up to the top of the hill, passing a viewpoint on the right. Follow the road down a couple of hairpin bends into Blaenrhondda. Take the second road to the right, and follow it for 1 km. Turn left just after a section of road with no houses on the left, and then left again at the next junction. When the road forks, turn right into the Penpych Woodland Park, then double back to the right into the car park. SS 9222 9902.
The first part of this walk is relatively easy, and makes a nice short walk. The second part must not be underestimated. It is a tough walk, and is very poorly maintained. Good footwear is essential. Good visibility is also needed. High water levels are good for most of it, but bad for the part near Nant Melyn and Nant Carnfoesen. Take care when walking around above the crags of Pen Pych, as there are occasional deep fractures in the ground, which must be avoided.
Take the very easy track from the end of the car park, which zigzags at first before climbing steadily. A steadily descending path on the left gives access to some cascades, but is not worth a detour if you are doing the full route. Berw Nant yr Ychen can be seen on a distant cliff through gaps in the trees. The track ends at a fenced viewpoint, with a small waterfall below it, and the tall Pen Pych waterfall ahead. A smaller stepped path continues over a tall cascade between those two waterfalls, to the base of the Pen Pych waterfall/Berw Wion. It then swings right and climbs up to the top of the cliff. For the easy walk, turn around at the base of the Pen Pych waterfall. (To the left is a path over the head of Nant yr Ychen, over to several small and a couple of dangerously exposed waterfalls in Nant y Gwair. These need a dedicated trip, and a very high level of ability. See the galleries for more information.)
Continue following the path around the edge of the cliff that runs around the Pen Pych buttress. Stay near the cliff edge, taking a right fork when the path splits, some way after Pen Pych. After crossing the remains of a stone wall, take another right fork, descending through forestry. When the path reaches a junction with another proper path, turn left, heading a little uphill, and follow it until it descends to a substantial metal bridge over the Rhondda Fawr. On the other side of the bridge is a junction of paths.
Turn left and follow the path to a junction of two streams. Cross the stream just upstream of the junction where a metal pipe acts as a bridge (take care in high water). Head up the right side of the other stream and cross a bridge, just before a tiny reservoir. Head up the left side of the reservoir above a deteriorating wall, and follow what remains of a path along the left side of the stream up to the Nant Melyn waterfall.
It is possible to see the Nant Carnfoesen waterfall from the path, but for the best view, cross the stream just upstream of the tiny reservoir, and head up the left bank of the other stream that enters the reservoir. Follow it up to the waterfall - there is no real path.
When you're done, return to the substantial metal bridge, and continue past it along a path running near the edge of a cliff. Take a small path that forks off on the right, and descends to the base of the Nant Drysiog waterfall, at a junction of poorly-defined paths; one ahead, one doubling back hard to the right, and one leading down ahead-right.
Take the path that doubles back on the right, and follow it to the main Rhondda Fawr waterfall, beside an old steam engine boiler, and disused mine level - there are several more little cascades below it, most of which can be seen best from the path. Return to the junction of paths.
Head down to the right past one more waterfall on Nant Drysiog hidden behind a concrete pipe, to another one hidden below the buildings below it - it can be tricky getting into a good viewpoint for this one.
Take the obvious track/road heading along the edge of the valley, starting at the buildings. Follow it for a long way, continuing ahead at a junction of tracks, until it reaches the edge of Blaenrhondda, and becomes a more substantial road. Turn left at a junction, then right a couple of times to cross the river. Turn left at the next junction. Either take a path to the right some way along here, which leads back to the car park, or stay with the road, turning right as needed, to get back to the car park.
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. You follow this description at your own risk.