What makes it curious is partly its shape, or rather the fact that its shape appears to have changed, at least on paper. The Ordnance Survey mapped it in 1842 as a roughly square enclosure planted with trees; by 1905 and again in 1935, the same maps show it as circular. Whether the ground itself changed, or whether earlier surveyors simply drew what they saw imprecisely, is not recorded anywhere with certainty.

The enclosure measures just under fifty metres across in both directions, enclosed by an earthen bank that stands less than a metre high on either side. Livestock have worn it down considerably, and bushes and trees have crept in along sections of the perimeter. The interior holds coniferous planting, with the south-western half lying level and the north-eastern half dropping away gently. Its proximity to Ballymacmoy House, now reached only by a disused avenue, suggests it may once have been part of a designed landscape, and one working interpretation is that it is a tree ring, an ornamental circular plantation used as a feature or shelter belt on estate grounds. Tree rings of this kind were common additions to Irish country house demesnes from the eighteenth century onward, though they can be difficult to distinguish from much older earthworks once the original planting has grown wild and the surrounding context has changed. Here, the ambiguity is part of what lingers.