The ravine itself drops sharply to a river below, and whoever built here understood that a sheer natural drop on one side was worth more than any amount of additional earthwork. Only the south-eastern portion of the structure survives, but what remains is enough to read the intention clearly.

The fort is what archaeologists classify as bivallate, meaning it was originally ringed by two concentric banks rather than one. Between those banks ran a fosse, a flat-bottomed ditch roughly five metres wide, designed to slow or expose anyone attempting an approach. The inner bank, built from earth and stone, stands about a metre high on its outer face; the outer bank is slightly lower and narrower. Together they enclosed a platform of ground on the ravine's edge, with the steep natural slope to the north rendering a third line of defence unnecessary. The overall enclosure was evidently large, though erosion, time, and the ravine itself have claimed the greater part of it, leaving only this south-eastern arc as evidence of the original scale. Earthwork forts of this kind are found across Ireland, ranging in date from the later prehistoric period through to the early medieval centuries, though without excavation it is impossible to say precisely when the people of Barbaha built and used this one.

The surviving earthworks sit close to the ravine edge, and the combination of the river below and the slumped banks above gives the site a quality that is easier to feel than to describe on paper. The measurements recorded are modest by any standard, but the logic of the place, the deliberate pairing of human construction with an unworkable natural drop, is still legible to anyone who walks the line of the remaining banks.