The Pen Twr Enclosure has been interpreted by some as as a ring cairn, although others have commented that it does not have the appearance of a prehistoric site. It is a circular and embanked enclosure, 16.7m in diameter internally, whose bank is 3.1m to 3.7m wide and 0.3m to 0.6m high. There is no trace of a ditch, entrance or internal features.

J.Wiles, RCAHMW, 5 April 2002