The rath at An Carn Mór Thiar does none of that. Sitting in low-lying pastureland in County Galway, it has been so thoroughly worn down over the centuries that its forty-three-metre diameter is defined by little more than a low bank of grassed-over stones, the kind of feature a casual walker might dismiss as a field boundary or a trick of the ground. A rath is a ringfort of earthen construction, typically enclosing a homestead or farmstead during the early medieval period, and this one preserves just enough of that original form to be recognisable as such, though only barely.

When McCaffrey catalogued the site in 1952, describing it as an earthen fort that was "very flattened and denuded", the monument was already well on its way to becoming landscape rather than archaeology. What survives today includes an irregular scarp running across the interior from north to south, creating a subtle but measurable drop of about one metre between the eastern and western sides. In the north-east quadrant, a small circular mound of earth and stone, roughly four and a half metres across, sits within the enclosure. Its function is unclear, though such internal features in ringforts can sometimes indicate a souterrain entrance, a hearth platform, or simply accumulated debris. A grassed-over stony bank, possibly connected to the main enclosing element, extends from the south-western side and runs north-west for approximately fifty-five metres, suggesting the original farm complex may have included an attached field or enclosure. A trackway has since cut across the monument from north-east to south-east, one of several ways the working landscape has continued to negotiate around, and through, what remains.