Thirty metres across, it sits in grassland at a point where the land to the west levels off and the ground to the east drops sharply down toward the valley floor. What makes it odd is not its shape but its interior: rather than rising ground contained within an earthen bank, the inside of the enclosure sits below the level of the surrounding field, giving the whole thing an inverted, hollowed-out quality.

When the first Ordnance Survey six-inch map was drawn in 1839, the site was recorded as a typical ringfort, the kind of circular raised enclosure built in early medieval Ireland, usually as a farmstead protected by an earthen bank and sometimes a ditch. The bank here still survives, modest in scale, standing roughly half a metre high on the interior side and slightly less on the exterior, and between one and two metres wide. But by the time the map was revised in 1899, something had changed in how the monument appeared: the hachures, the small lines surveyors use to indicate slope and relief, were now facing inward, indicating a large circular hollow rather than a contained interior. A lime kiln, a structure used to burn limestone and produce agricultural quicklime, is marked on the earlier map immediately to the north-east of the site. It is possible that material was quarried from the interior of the enclosure to feed that kiln, gradually scooping out what the original builders had shaped by cutting a terrace into the hillside. If so, the enclosure has been altered by the same agricultural economy that once surrounded it, its interior gradually consumed in the service of improving the land nearby.