Porth-yr-Ogof and the Waterfall Country caves
In Waterfall Country, to the south of the Brecon Beacons, you can admire the largest and most impressive cave entrance in our National Park and visit numerous smaller caves.
At Porth-yr-Ogof, the entire Afon Mellte is swallowed by the earth.
To reach this magnificent cave entrance from Cwm Porth car park, you descend a steep and uneven twisting path. Don’t venture further than the immediate entrance of the cave. Take special care during or following heavy rainfall as the cave entrance floods quickly and the footpath leading to the cave is hazardous when wet.
Though less extensive than their cousins to east or west, the cave networks around Ystradfellte and Penderyn are nevertheless very interesting.
The Little Neath River Cave which takes the flow of the Nedd Fechan or Little Neath River is animportant system. A view of the resurgence beside the Nedd Fechan known as Pwll Du or the Black Hole (SN912121) can be enjoyed by the non-caver taking the footpath upriver for a mile from the car park at Pont Melin-Fach.
An extraordinary swallow hole is that of Pwll-y-Felin beside the minor road between Penderyn and Ystradfellte (SN942121). In wet weather the stream delivers water into this large crater faster than the cave beneath can take it away so it can fill to the brim.
There are a handful of small caves around Dinas Rock at Pontneddfechan and some in the valley of the Afon Hepste. The section of this river where Hepste Bridge crosses it (SN945112) is dry in all but the wettest weather as its flow has retreated underground upstream at Ogof Glan Hepste.