The earthen bank enclosing this ringfort at Oldcourt reaches a maximum height of 3.6 metres, and the circular enclosure it defines measures around 30 metres across. A shallow fosse, the ditch that typically rings such earthworks on the outside of the bank, follows the perimeter, and there are breaks in the bank to the north and east. The interior has been raised on its western side, a practical adjustment to compensate for the natural slope of the hillside, so that the living floor inside would have sat roughly level.

Excavation by O Cuileanáin, published by Murphy in 1961, filled in much of what the surface alone could not tell. The fosse, which appears shallow from the present ground level, proved to be six feet and six inches deep when properly measured, a reminder of how much earthworks can settle and silt over a millennium or more. The eastern break in the bank was the formal entrance, and the excavators found evidence for both a wooden gate and a causeway crossing the fosse at that point. Inside, three hearth sites were uncovered, along with two overlapping oval house foundations, each roughly thirty-three to thirty-nine feet in their dimensions, suggesting the site was occupied over more than one phase. In the south-western quadrant, a souterrain was also recorded. A souterrain is an underground stone-lined passage, typically associated with Early Medieval ringforts, and thought to have served for storage, refuge, or both. Together, the hearths, the overlapping houses, and the underground passage suggest a site that was lived in, modified, and returned to across generations rather than built and abandoned in a single episode.