A rath is a ringfort, the most common monument type in the Irish countryside, typically built during the early medieval period as a defended farmstead for a family of some local standing. What survives at Ballycapple is a circular enclosure roughly 32.7 metres across, set just below the crest of a ridge that slopes away to the north-east. The defining features are still legible in the ground: an inner bank, a wide U-shaped fosse or ditch nearly a metre deep, and an outer bank beyond that. The entrance, a causewayed gap about 4.5 metres wide, faces the east-north-east.

The earthworks are built mainly of soil, though the outer bank has had stone added to it at some point, and has since been absorbed into the field boundary system, a common fate for prehistoric and early medieval earthworks in agricultural landscapes where any available material tended to get put to practical use. The inner bank has been largely worn down to a scarp rather than a proper raised bank, suggesting centuries of grazing and weathering have taken their toll. The interior is described as much overgrown and sloping northward, giving the enclosure a slightly uneven quality that the original builders, who would have built on the most defensible ground available, presumably accepted as a reasonable compromise for the ridge-top position.