Herbert's Quarry to Llyn y Fan Fach Circular

This is a beautiful trail in the Y Mynydd Du (Black Mountain) region in Bannau Brycheiniog National Park (Brecon Beacons), taking you on an undulating, winding path up to Waun Lefrith, overlooking Llyn y Fan Fach.

The trail starts from a car park along the A4069 near Herbert’s Quarry, an abandoned limestone quarry, and takes you on the first ascent up to Garreg Lwyd. Enjoy the stunning views from each peak as you continue northeast, visiting Foel Fraith, which is marked by a cairn.

You’ll pass Ogof Poll Swnd on its northwestern flank before heading northward across the rocky ridge of Garreg Las towards Carreg Yr Ogof, though this cave can be difficult to find.

From here, head east and make your way up Waun Lefrith. On a clear day, you’re greeted with incredible views down to Llyn y Fan Fach, nestled in the cwm below. According to Welsh folklore, this lake is said to be inhabited by the Lady of the Lake.

You’ll also have an amazing view of the rest of the Carmarthen Fans and the steep escarpments.

The return route follows a parallel path that avoids the majority of the peaks, heading back over Cerreg Yr Ogof, along the western slopes of Garreg Las, and skirting the top of Foel Fraith along its northern slopes, where there is another cave, Dan Y Lleuad Wen, a little further up the slope.

Loosely follow the meandering Afon Clydach along the base of Garreg Lwyd. Veering away from the stream, you’ll reach Herbert’s Quarry, which makes for an interesting visit to finish the trail with. It is also a popular place for rock climbing.

Dogs are welcome on this trail, but keep in mind that you may encounter free-roaming sheep, so leads are advised.