The name 'Corn Du' translates from Welsh as 'Black Horn'.
It is technically classified as a mountain in Wales exceeding 2,000 feet, often referred to as a 'Hewitt'.
The summit includes a man-made stone cairn that marks the elevation point.
The peak is a significant location for SAS selection marches, known locally as the 'Fan Dance'.
The north face of Corn Du contains a sheer, craggy drop known as the Craig Cwm Llwch glacial cirque.
It is separated from Pen y Fan by a narrow, high-altitude col known as Bwlch Du.
The mountain was formed by glacial erosion during the last ice age, shaping the steep cliffs on its northern flank.
Corn Du is the second-highest peak in the Brecon Beacons, reaching an elevation of 873 meters. It is situated on the same ridgeline as Pen y Fan, located approximately 0.8 kilometers to the northwest of the highest summit. The peak is characterized by its prominent pyramid-like shape when viewed from the south and west. It serves as a major waypoint on the popular traverse between Storey Arms and Pen y Fan. The summit features a distinct, flat, rocky plateau that contrasts with its steep slopes. It is a key point within the Fforest Fawr UNESCO Global Geopark. The geology consists primarily of Old Red Sandstone from the Devonian period. The area is part of a high-altitude moorland ecosystem prone to rapid weather shifts.
The southern ridge looking toward the peak, which captures the mountain's distinct triangular profile.
Always carry a physical topographic map and compass, as mountain weather frequently obscures digital GPS signals.
Wear moisture-wicking layers and waterproof outer shells, as conditions at the summit are significantly colder than at the trailhead.
Start your ascent early to secure parking at the nearby trailheads, which reach capacity quickly on weekends.
Attempting the climb in poor visibility without navigation skills or during high-wind weather warnings.
Follow the Countryside Code: take all litter home, keep dogs on leads near livestock, and stay on marked paths to prevent erosion.
