Yet beneath the grass lies the remains of a crannog, an artificial island constructed by early inhabitants who built upward from a waterlogged foundation rather than simply choosing drier ground. Most crannogs in Ireland are associated with the early medieval period, used as defensible lake dwellings, but this one is considerably older, its origins reaching back to the Early Bronze Age.

Excavations carried out by Seán P. Ó Ríordáin in 1946 revealed the engineering behind the mound. He found that the island had been made by laying a stone layer over a foundation of peat, brushwood, and timbers, the foundation extending to roughly eleven metres in diameter and the stone layer above it to about eight metres. A fragment of Beaker pottery, a type of decorated ceramic associated with communities living across Atlantic Europe during the late Neolithic and Early Bronze Age, was recovered from a hearth on the site. That single find was enough for Ó Ríordáin to conclude the crannog could be no later than the Early Bronze Age, placing its construction somewhere in the broad span of the third to second millennium BC.

The mound today measures roughly 21 metres on its northeast to southwest axis and 12 metres across, and what remains of the surrounding bank stands only a matter of centimetres above the interior. A shallow circular depression, about five metres in diameter and fifteen centimetres deep, sits towards the southwest of the interior. A well and pump house lie to the east-northeast, and a land-drain runs along the south side. The flood plain setting of the Camoge River would have made the original construction both practical and purposeful, placing the settlement in what was once a genuinely watery environment. The site now sits quietly in agricultural land, easy to overlook but carrying, in its slight undulations, the trace of something built with considerable deliberate effort nearly four thousand years ago.