The enclosure, roughly forty metres in diameter, only revealed itself clearly from the air, when a cropmark showed the arc of its fosse curving from the north-west around to the south-west. A fosse is simply a ditch, the defining feature of a rath or ringfort, an earthwork enclosure used throughout early medieval Ireland as a farmstead, its bank and ditch demarcating a household's space from the wider landscape. What the aerial photograph also suggested is that a curved field fence running from the south-west back to the north-west may follow the original bank of the enclosure, farmers of a later era having absorbed the old earthwork quietly into their own boundaries without ever quite erasing it.

The aerial survey that caught this cropmark was carried out in July 1989. At that time of year, differential moisture retention in the soil above buried features can cause overlying crops to grow unevenly, producing the pale or dark marks that reveal what lies beneath. The enclosure sits in a field that appears to be unusually rich in similar features: a possible second ringfort lies roughly twenty metres to the north, a circular enclosure of unknown character sits about fifty metres to the north-north-east, and a further enclosure has been recorded around eighty metres to the north-east. Four potentially related sites clustered within a single field is a striking density, suggesting this corner of the Blackwater valley may have supported a concentration of early settlement activity rather than a single isolated farmstead.