It is the kind of place that registers on old maps as a neat geometric shape and on the ground as something considerably more ambiguous, a raised ring of earth with a level floor inside, swallowed by vegetation and easy to walk past without realising what it is.

The enclosure is roughly thirty-five metres in diameter, defined by an earthen bank that rises about seventy centimetres on the interior side and a more pronounced one point three metres on the exterior, the difference in height suggesting the bank was thrown up from material dug on the inside. Earthwork enclosures of this kind are among the most common archaeological monument types in Ireland, often associated with early medieval settlement, though without excavation it is impossible to say more about when this particular one was built or what it was used for. What is clear is that by 1842, when the first edition of the Ordnance Survey six-inch map was compiled, the enclosure was already being treated as a deliberate landscape feature, shown as a circular form and planted with trees, which implies it had acquired a kind of ornamental status within the grounds near Frankfort House. That planting may well be part of why the interior is now inaccessible, the trees and subsequent undergrowth having closed the site off over the intervening century and a half.