The summit lies on a ridge stretching from Talybont Reservoir in the east, to the A470. About to the south-west lies the subsidiary top of Corn Du, beyond which the terrain drops at a moderate angle to the subsidiary top of Y Gyrn then more steeply to the Storey Arms on the A470. To the east, the ridge drops steeply to the col connecting it to Cribyn, the next mountain along the ridge. From Corn Du, a ridge with an east-facing escarpment descends south towards Merthyr Tydfil.