From Three Rock, the trail ascends to the summit of Two Rock Mountain (). Known as Fairy Castle, this is the highest point on the Dublin Mountains Way. The summit is marked by a cairn and a trig pillar. These two features lie upon a raised mound, approximately across and high and covered in turf and heather: this is the remains of a passage tomb. Due to the collapse of the edges of the cairn, the entrance to the passage can no longer be seen.