A natural coastal knoll has been enhanced with a rampart and ditch to form a promontory fort. The knoll has been eroded by the sea on the north-west and north-east and only a near square area about 18m across remains of what may have been a rather larger enclosure.

The 1.8m deep ditch on the south-east side takes advantage of a natural gully and on this side the rampart rises 3.4m from the ditch bottom. Slighter banks on the north-east and north-west sides are probably old field boundaries. No finds are known from the site and its original date is unknown. It is perhaps most likely to be a later Prehistoric or Roman period fort. The traditional identification as a medieval earthwork castle ['Castell - site of': on OS County series 1st edition (Anglesey V.12 1889)] is more unlikely.

Source: RCAHM Anglesey Inventory (1937), 68-9

John Wiles, RCAHMW, 13 August 2007.