The northernmost of two large cairns named as Carn Gwilym, above the eastern side of the Hyddgen valley. The cairn was 14m east-west by 12m and 0.6m 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 289724, towards the southern edge of it. A small shelter, NPRN 289725, had been built into the eastern edge of the main cairn. A small stone cairn, NPRN 289726, lay to the southeast of the main cairn. J.J. Hall, Trysor, 6 October 2006J.J. Hall, Trysor, 6 October 2006