That boundary, in fact, is precisely how the site appears on Ordnance Survey maps from 1846 and 1894, where it cuts across what was once a circular earthwork roughly forty metres in diameter. The juxtaposition is quietly telling: centuries of agricultural reorganisation laid over something far older, and yet the older thing has not entirely disappeared.

The site belongs to a class of monument known as a rath, the Irish term for a ringfort, which was the most common form of rural settlement in early medieval Ireland, typically dating from around the sixth to the twelfth centuries. A rath usually consisted of a circular earthen bank enclosing a farmstead, sometimes accompanied by a fosse, or external ditch, and occasionally by an underground passage called a souterrain, which may have served for storage or concealment. At Barleymount, most of the original bank has been levelled, and the perimeter survives mainly as a faint rise or scarp along the south-western, north-western, and north-eastern arcs. The south-eastern arc is better preserved, where a scarp still stands to a height of around two and a half metres. To the east-south-east and south, a fosse roughly two metres wide at its base remains visible, and beyond it an outer bank, nearly six metres wide and standing about one and a half metres above the surrounding ground, can still be traced. The presence of an outer bank alongside the fosse suggests this was a more substantial enclosure than many, possibly the homestead of a family of some local standing. A possible souterrain in the western sector adds further depth to the picture, though its extent has not been fully established.