Grwyne Fechan and Pen y Gadair Fawr, Brecon Beacons National Park, Powys

At 2,624 feet, Pen y Gadair Fawr is the sixth highest peak in Brecon Beacons (Bannau Brycheiniog) National Park, within the Black Mountains, and it may be reached from several directions, including east through the Mynddu du Forest, and south, starting from the end of a country lane 3.5 miles north of Llanbedr, the hike described here; a loop of 6.3 miles, of which about 2 miles is off-trail.

The route is through a corridor of trees alongside the Grwyne Fechan river, along a track into a conifer plantation then beside a smaller stream, Gargwy Fawr (later Gargwy Fach), which drains the south side of the peak, and up the slopes to the summit. They return route is north along the ridgeline a little way and down a similar stream, Nant y Gadair, which meets Grwyne Fechan, and finally south along this drainage back to the start point, passing three ruined sheepfolds and a historic bridge. Near the start is another old structure, the ruins of Hermitage, a mansion from the early 19th century.

The whole area is very little visited so offers perfect solitude and a good mix of scenery, including a succession of pools and cascades along the streams, and it gives great views all across the national park, from the upper elevations.

Location

Llanbedr is a small settlement beside the Grwyne Fechan; the main road through the village continues northwards across the western slopes of the valley eventually descending, coming close to the river, and reaching a fork after 3.5 miles, a suitable place to park. The left branch is a short, gated track to Darren farm while the other fork is still paved for a short distance then also becomes a track, and this forms the first part of the hike.

Hermitage

From the parking place, the paved road extends another 1,000 feet, through woodland and alongside a field, where it becomes unpaved, and soon crosses the Grwyne Fechan on a bridge, just upstream of the confluence with Gargwy Fawr, an east-side tributary. A few yards before, another track fords the river and heads back downstream to the ruins of Hermitage, which was built in the 19th century as a hunting lodge and during World War 1 was briefly used to house German prisoners of war, after which it reverted to private occupation, before being abandoned in 1937. The roof is long gone but the walls are still substantial and the location is quite striking, right beside the river, flanked by tall conifers to the east.

Gargwy Fawr

Just beyond the bridge, the track forks again, at the start of the loop portion of the walk. The right track follows Gargwy Fawr upstream, soon entering a large conifer plantation, some parts of which have recently been cleared. After 1.2 miles the track curves abruptly uphill to the west, and ahead is a short but very overgrown pathway through new growth trees, that descends gradually and emerges from the lower edge of the plantation, beside the stream (now the Gargwy Fawr), which is followed up a broad valley over many cascades, until it splits into little tributaries as the slopes become steadily steeper.

Pen y Gadair Fawr

Eventually the gradient lessens, the ground levels out and the big cairn at the summit of Pen y Gadair Fawr comes into view. The peak is quite well-defined, unlike the flatter, extended summit of Waun Fach, half a mile north. Paths run south, east and north from the summit; this latter descends, partly via some granite steps, and approaches a broad valley to the west, down which flows another stream, Nant y Gadair, an upper tributary of the Grwyne Fechan.

Nant y Gadair

Like Gargwy Fawr, Nant y Gadair is easy to follow, walking downhill alongside the stream, past just a few places where the Old Red Sandstone bedrock is exposed, down nearly 1,000 feet over one mile to the confluence with the main upper fork of the drainage. Just above and below the confluence are the ruins of two sheepfolds, one named Ffald y Nant. A faint path appears at the second, running along the west side of the river over open slopes, on to a third such ruin (Ffald Fawr), rather bigger. On the opposite side of the river are more conifers from the plantation. After another few minutes walking the path joins a track which soon crosses the river on the ancient Tal-y-maes Bridge then climbs gently through fields, past the junction with the driveway of Tal-y-maes farm and finally down a slope back to the river, and the junction at the start of the loop walk.