Cairn situated on a prominent SW to NE aligned ridge of volcanic rock crossing the summit of Mynydd Rhiw. This is one of six cairns located on the mountain, this and four others (NPRNs 308048, 302261, 302262, 421096) are sited along the same ridge and the sixth (NPRN 302257) to the west.

The cairn sits on a high point of the ridge and is one of the largest, comprising a wide spread of stone 23m in diameter that is partly mixed with natural scree. Within this spread a 10m diameter pile stands up to 3m high and has a number of modern structures/shelters constructed in it.

Louise Barker, RCAHMW, July 2015

Sources:
RCAHMW, 1964 Caernarfonshire vol III. A Survey and Inventory by the Royal Commission on the Ancient and Historical Monuments of Wales. (Mon. No. 1537 and plate 3)
OS495card; SH22NW2