Known as Lisillaundarrig, or Lios Oileán Garbh in Irish, it appears in official records as a ringfort of the rath type, meaning an earthen enclosure, yet the surviving stonework tells a more complicated story. A researcher named Curran, examining the site independently, concluded it was in fact a cashel, the term used for a stone-walled enclosure of similar early medieval date and function. Both forms were typically used as enclosed farmsteads, housing a single family and their livestock, but the distinction matters to those trying to read what remains in the ground.

The site is univallate, encircled by a single boundary rather than the multiple concentric rings found at more elaborate examples. Internally it measures 30 metres north to south and 19 metres east to west, with the floor of the enclosure sitting slightly higher than the surrounding ground. For much of its circuit the boundary has reduced to a low scarp, but at the south-west a stone revetment, a retaining face of upright or carefully placed stones, survives to about half a metre in height over a 15-metre stretch. When Curran visited, he recorded the original wall as having been roughly 2.1 metres wide, with a ledge or terrace built into it about 36 centimetres above ground level. In the north-west corner of the interior, a mound of stones marks what the Ordnance Survey maps record as a clochaun, a small dry-stone corbelled structure, a type sometimes described as a beehive hut, though little of it now remains legible. Loose stones scattered across the site may represent field clearance rather than structural collapse, which makes it harder to reconstruct the original layout with confidence. The northern portion of the enclosure was destroyed by the construction of a trackway, and what remains is fragmentary, its best-preserved stretch being that south-western revetment where two metres of inner wall-face still stand to a height of 25 centimetres.