Pen Cerrig-calch

Pen Cerrig-calch is a subsidiary summit in the Black Mountains, part of the Brecon Beacons National Park in southern Powys, Wales. It stands 701 metres above sea level, marked by a trig point near its peak. The hill rises above the narrowing River Usk valley, looking down on the small town of Crickhowell. Views stretch westwards to the main Beacons and along the ridge to other high points. A narrow ridge leads northwest to Pen Gloch-y-pibwr, then north to Pen Allt-mawr’s secondary top at 719 metres, also topped by a trig point. The hill’s unusual geology includes mudstones and sandstones from the Old Red Sandstone period, with a band of Carboniferous Limestone around the summit. This limestone creates small shakeholes and gives the hill its name, meaning ‘top of the limestone rock’. The summit itself is made of pebbly sandstone from the Carboniferous period. A steep cliff called Darren marks the southwestern edge, formed by a large landslip after the last ice age. Below Darren lies a jumble of boulders and uneven ground from the slipped strata. The most striking feature is Crug Hywel, an Iron Age hillfort on the southeastern spur, also known as Table Mountain. Ancient cairns mark the main summits, and small disused quarries dot the lower slopes where Old Red Sandstone was once cut. The upper slopes are open access land, reached by footpaths from the Usk Valley and the Grwyne Fechan valley. The Beacons Way skirts the southern and western flanks, while the usual route to the top follows the spur from Crug Hywel.