The southernmost of two large cairns named as Carn Gwilym, above the eastern side of the Hyddgen valley. The cairn was 13m east-west by 12.5m and 0.5m high. The external 1m perimeter of the cairn was turf covered but the rest of the cairn was clear of vegetation. The top of the cairn was level, with a later, distinctive upright cairn, NPRN 289721, towards the western edge of it. A small cairn, NPRN 289722, lay to the east of the main cairn. J.J. Hall, Trysor, 6 October 2006