A cashel is a stone-built ringfort, typically of early medieval date, its boundary formed not by an earthen bank and ditch but by drystone walling and, in this case, a steep scarp faced with massive boulders where the wall alone was insufficient. What makes the site at Ballynahowna quietly peculiar is how thoroughly later activity has muddled that early form: a field boundary cuts the enclosure almost exactly in half, and the corrugated ridges of lazy beds, the narrow cultivation strips associated with post-medieval and famine-era tillage, run across what was once a defended interior.

The cashel's perimeter runs from the SSE around to the north as a grass-covered wall of drystone masonry mixed with small quantities of earth, while the remainder relies on that scarped and boulder-faced edge. No fosse, the external ditch that often accompanies earthen ringforts, was ever part of the design, and whatever the original entrance looked like, it is no longer identifiable on the ground. Inside, near the north-west of the bank, a small rectangular hut site survives, its narrow entrance, just 0.6 metres wide, set in the centre of its north wall. Projecting outward from the scarp at the south-south-west is a small square structure with exceptionally wide drystone walls, each 2.7 metres across, though only three stones of the south-east side remain upright; it may have served as an animal shelter. A possible souterrain, an underground stone-lined passage of the kind used in early medieval Ireland for storage or concealment, has also been identified within the enclosure, adding another layer to a site that has clearly served many purposes across a considerable span of time. The views from the slope open out in most directions, with the Easky River lying just 150 metres to the east, though higher ground to the south-south-west closes things off in that quarter.