A cashel, which is the Irish term for a stone-walled ringfort, once stood here, its circular perimeter of drystone masonry enclosing a space roughly 27.4 metres across. Today, no visible surface trace survives. The field gives nothing away.

The site was recorded by McCaffrey in 1952, classified as a circular stone fort defined by a collapsed drystone wall. At the time of that record, the structure was already in poor condition, its wall reduced to a spread of rubble rather than a standing enclosure. Cashels of this kind were typically built during the early medieval period, serving as defended farmsteads for a single family or small community, the stone construction distinguishing them from the more common earthen ringforts found across Ireland. What caused the wall at Drumharsna to collapse entirely, and when the last traces were finally absorbed into the surrounding ground, is not recorded.