The one at Ballycoskery, sitting in pasture roughly fifty metres east of the Awbeg River in north Cork, is more elaborate than that. Three concentric earthen banks survive here, each separated from the next by a fosse, the term for the ditch from which the bank material was originally dug. The innermost bank still stands to an external height of 0.65 metres, and its surrounding fosse, four metres wide, holds water along its northern, eastern, and southern edges. The middle and outer banks are lower and more worn, but the overall plan of the enclosure, roughly thirty-one to thirty-two metres across, is still legible in the ground.

A ringfort with three banks and two fosses, sometimes called a trivallate rath, is considerably less common than its single- or double-banked counterparts, and their relative rarity has led some archaeologists to associate them with higher-status occupants, perhaps a local lord or a family of some regional importance in the early medieval period, broadly the fifth to twelfth centuries. Whether that held true here is unknown; no excavation record is attached to this site. What is clear from the physical evidence is that someone invested considerably more labour in the defences at Ballycoskery than the typical farmstead would have required. The entrance faces east, a common orientation for ringforts, possibly for practical reasons related to morning light and prevailing wind, or simply convention. A later drain has disturbed the middle and outer banks to the north-east, and that corner of the monument shows the kind of low, irregular disturbance that drainage work across Irish farmland has left on countless earthworks over the centuries.