A rath, the Irish term for a ringfort, is a roughly circular enclosure defined by an earthen bank and ditch, built during the early medieval period and used primarily as a farmstead and enclosure for livestock. Thousands once dotted the Irish countryside; many have been ploughed away or built over entirely. This one at Gortnamona endures, if in diminished form.

The rath measures 29 metres in diameter and is defined by a degraded scarp, meaning the original raised bank has slumped and eroded over the centuries until it reads more as a slope in the ground than a proper earthen wall. A gap of roughly 3.5 metres on the east-northeast side may represent the original entrance, the point where people and animals once moved in and out of the enclosure. Whether that opening is genuinely ancient or the result of later disturbance is difficult to say with certainty, but the alignment is consistent with entrance orientations commonly found on Irish ringforts, which frequently faced eastward.