It is not an island in any natural sense. Beneath the trees and dense rush growth is a circular stone cairn approximately twenty metres in diameter and three metres high, the submerged and overgrown remnant of a crannog, an artificial island dwelling of the early medieval period typically constructed from timber, stone, and brushwood to provide a defensible or prestigious residence in a lake.

The site was documented by O'Sullivan in 2004, who noted its position at the south-eastern end of Lough Ennell, directly opposite the point where the River Brosna flows southward out of the lake. That geographical detail is not incidental. Crannogs were rarely placed at random; proximity to a river outflow would have made this location meaningful in terms of movement, fishing, and control of water routes. The cairn itself, though heavily vegetated, retains enough mass to suggest a substantial original construction, and its survival in two metres of water has likely protected it from the kind of interference that has damaged more accessible monuments.