This hill-fort was constructed during the Iron Age (600 BC – AD 100) and is found on the mountain between Aberdare and Merthyr (SO 0271 0405). The fort is unfinished and this gives the fort its semi-circular shape. The entrance was intended for the east end of the rampart, the diameter of the rampart is 52m and the bank, ditch and counterscarp bank are 11m wide by 2m high. Within the fort are two rare platform cairns. Platform cairns are dated as Bronze Age, mainly between 1700 and 1200 BC. Standing 0.3m high, each cairn is slightly oval. The largest measures 11m by 10.1m and the smaller is 7m by 6.1m.
Ref. Royal commission on Ancient and Historical Monuments in Wales : Glamorgan Vol.1 Part1,Tthe Stone and Bronze Ages. 1976. Page 67.
Royal Commission on Ancient and Historical Monuments in Wales : Glamorgan Vol.1 Part 2, The Iron Age and the Roman Occupation. 1976. Page 22 – 23.
CADW Scheduled Ancient Monument Record : GM239(RCT) Gwesyll. (Report).