Pen Pumlumon Arwystli I is the most southern of three large Bronze Age stone cairns on top of Pen Pumlumon Arwystli (the others cairns being Nprns 304830 and 304831). It is a centrally cratered, circular cairn, c.20m in diameter and 2.4m high. 3m to the SE is a possible further cairn, 4.0m in diameter and 0.2m high.

(source Os495card; SN88NW2)
RCAHMW AP955039/68-70
J.Wiles 15.04.02