Little known and seldom celebrated, these towering rocky crags are within an hour’s drive of Cardiff and Bristol – yet people insist on travelling further in search of such mountainous drama.
This was once a huge quarry in the 18th and 19th centuries. Here, limestone was hewn from the ridge and taken by tram to the Monmouthshire and Brecon Canal in the valley below. It was then burnt in kilns for use as fertilizer, whitewash on cottages, and as a vital part of the iron-making process when the southern Welsh valleys were awash with pits and furnaces.
Now the area is peaceful – the mews of buzzards, croaks of ravens and bleat of sheep having replaced the noisy toil of quarrymen. Occasionally you may hear the clink of harnesses and thud of heavy boots as cavers emerge from secret passages deep in the hill. The limestone is riddled with – frankly terrifying – tunnels both man-made and natural.
The gentle, level tramway winds its way around the ridge into Craig y Cilau National Nature Reserve, with the drops below becoming ever more precipitous.
The path hereon is littered with stones and tree roots but leads you into mossy hazel and oak woodland, where in spring you may very possibly find a lesser spotted woodpecker. The mood change from stark rock to cool, soft green is astonishing, though the crags still frown through the canopy, appearing to overhang the land below.
Eventually the wood opens up into a patch of rare, wildflower-rich bog – wellies are advised. At the western edge of the reserve, 50 yards beyond the information sign, you can loop back to the woods following a footpath through farmland.
1. Towards the ridge
Follow the path west out of the car park, past a barrier. The views over the Usk Valley are breathtaking. Look for Crickhowell nestling in the valley below, and the distinctive shape of Sugar Loaf to the east. Turn right 20m before the ruined building and pick up a narrower grassy path. Willow warblers and redstarts sing from the scrub. Bear left around the top of the paddock and pick up the disused tramway. Follow the path into a fascinating lunar landscape of grassy hillocks and continue past the steep quarry face, home to ravens, jackdaws and peregrines. Drop down to the lower path and continue left. Keep to the lower path until you reach a gravelly path curving round to the left. Keep on the path, round the crags and soon you reach an information post and enter the Craig y Cilau nature reserve.
2. Into the reserve
Continue on the path as it follows the cliff edge, with ravens and buzzards soaring above. Turn right at a yellow path marker and keep following the yellow waymarkers down into the valley through tangled ash, oak, rowan and beech to meet a stream. When you reach a marker with four yellow arrows, turn left and walk to an area of raised bog, Waun Ddu, with a range of mosses, grasses and sedges. Skirt the stream and then cross it, aiming for the clear grassy path on the hillside ahead. Follow it uphill, past an information point and out of the reserve.
3. Over farmland
Turn right and go through a gate on your right. Head down the farm track, then turn right at a sheep paddock (look for a faded white marker) and head downhill through the field. Turn left over a stile, then continue downhill in the direction of the stream. Cut across a field and climb a stile. Continue in this direction, crossing several fields, to reach a long gap in a stone wall. Bear right to reach a wall beside the stream then follow this left. You will soon pass a small ford then come to a field with a double stile in the corner. Ignore the stile and instead climb a low gate 10m to the left. Pick up a grassy path that winds through bluebells under the trees to the left of the stream. On a warm spring day, you will be deafened by the songs of thrushes, warblers and tits.
4. Back to the start
Cross a stile, then stepping stones over the stream, before climbing out of the valley. When you come to a junction, turn right steeply uphill. Turn left on to a main path, then head on to a track behind a row of cottages. Turn right at a stile before you reach the road and follow a path through trees. Climb the next stile and continue uphill, then cross a stile and follow a path through bracken, uphill and diagonally left until you reach the tramway. Turn left and follow the path back to the car park, bearing left where the path splits at the ruined house.
Click on the map below for an interactive version of the route.