This enclosure is sited upon the north-eastern flank of Allt Du, which forms the terminal of Cefn Cwm Llwch, northern ridge of Pen-y-Fan.
According to Coflein:
‘A somewhat hooded enclosure, c.100m by 60m, set on a north-east facing hillslope, defined by a bank and ditch, except to the north, where a weak bank is said to have existed.‘