Look more carefully and it resolves into something considerably more structured: a double-banked ringfort roughly 32 metres across, its ditches still waterlogged along the north-east, east, and south-west arcs, holding water as they have for well over a thousand years.

Ringforts, known in Irish as raths when they are earthen rather than stone-built, were the dominant settlement form of early medieval Ireland, typically serving as enclosed farmsteads for a single family and their livestock. This one at Coolmoyne follows the general pattern but preserves its double enclosure with reasonable clarity. The inner bank, about 9 metres wide and rising nearly one and a half metres above the exterior ground level, is breached in three places, at the west, north, and east-south-east, the last of these coinciding with a matching gap in the outer bank. That alignment is unlikely to be accidental; it probably marks the original entrance, where run-off from the fosse, a surrounding ditch roughly 6 metres wide and 0.7 metres deep, was channelled outward through a depression still visible on the exterior. The outer bank survives best along the east-north-east to south arc. Elsewhere the banks have been worn to little more than a scarp. A quern stone, a flat rotary grinding stone used to mill grain by hand, was noted in the adjoining farmyard by Cahill in 1982, a small domestic object that hints at the ordinary working life once conducted within these banks.