The feature is a rath, the most common type of early medieval enclosure in Ireland, typically built as a farmstead surrounded by a circular earthen bank and, sometimes, a ditch. This one is modest and worn, and it would be easy to walk past without registering what you were looking at.

The rath at Lismoylan sits on a south-facing slope in what is now level pastureland, a setting that would have made practical sense to whoever chose to build here, offering reasonable drainage and a degree of natural shelter. It measures roughly 24.4 metres in diameter, which puts it at the smaller end of the rath spectrum. The defining bank survives to a width of about 0.9 metres, though its internal height has been reduced to just 15 centimetres in places, suggesting centuries of ploughing, grazing, or simple weathering. The external face of the bank is better preserved, still standing to around 0.9 metres, and the most legible sections are found on the northern and eastern sides. The site was recorded by McCaffrey in 1952, catalogued as entry 146a in what appears to have been a systematic survey of the region.

The earthwork's poor state of preservation is itself part of the story. Most raths in Ireland have been reshaped or partially destroyed by agricultural activity across the centuries, and this one is no exception. What remains is enough to read the original plan, a tight circular enclosure that once separated domestic life from the surrounding landscape, but not enough to project much more onto it. The northern and eastern sections, where the bank has fared better, are the most rewarding to examine if you want a sense of the original profile.