No earthwork rises above the field surface, no stones mark the perimeter, and to a walker crossing the farmland there is nothing to suggest that anything of significance lies underfoot. The site announces itself only from the air, and only under the right conditions, when differences in soil moisture cause the crops above buried features to ripen at slightly different rates, producing faint rings and lines visible as cropmarks.

What those cropmarks reveal is a ring barrow, a type of prehistoric funerary monument typically consisting of a central mound surrounded by one or more circular ditches, or fosses. At Rathellin, aerial photographs have identified not one but three concentric fosses enclosing a roughly circular area with an estimated maximum diameter of around 100 metres. A central mound, once presumably raised above the surrounding landscape, has been levelled by centuries of ploughing. The photographs, referenced in the Archaeological Inventory of County Carlow published in 1993, include images taken as part of aerial survey work carried out in 1989. The site is noted as comparable to the Fenniscourt Barrow elsewhere in the county, and lies close to a related feature recorded separately as the Rathellin ring-ditch. Much of what is now known about monuments of this kind in Carlow comes from the aerial survey work of G.F. Barrett, whose research through the 1990s and 2000s systematically documented the county's buried and plough-levelled archaeology from the air, recovering a landscape of sites that conventional ground survey had entirely missed.

Because the monument survives only as a cropmark, there is little for a visitor to observe on the ground itself. The significance of the site lies less in what can be seen in the field than in what it represents: a large, elaborately structured funerary enclosure, probably prehistoric in origin, that has been quietly erased from the surface while remaining legible, to those with the right vantage point and the right season, in the pattern of the growing crops above it.