The rath at Corkagh Beg sits on a low natural rise in poorly drained pasture in County Sligo, and despite the unremarkable surroundings it commands clear sightlines in every direction, which was almost certainly the point.

A rath, sometimes called a ringfort, is a roughly circular enclosure defined by one or more earthen banks and ditches, built during the early medieval period in Ireland as a farmstead or high-status homestead. The example at Corkagh Beg is more imposing than many of its kind. The central platform measures approximately 28 metres across and is raised considerably above the surrounding ground. The bank running along its top is nearly eight metres wide, and while the inner face drops gently by only about half a metre, the outer slope is considerably more dramatic, falling away by nearly five metres on the north-north-east side. Around the base of that platform runs a fosse, the defensive ditch characteristic of these monuments, itself varying in width between roughly two and a half and three and a half metres depending on where you measure. Beyond the fosse sits a further outer bank. The original entrance survives on the east-south-east side, where matching gaps two metres wide cut through the concentric banks, connected by a ramp-like causeway across the ditch. Perhaps most telling is the evidence of stone kerbing along the inner bank faces on either side of that entrance, suggesting a degree of finish and structural care that goes beyond simple earthwork.