Locally known simply as a fort, the roughly D-shaped enclosure measures about 35 metres across, defined by the worn-down remains of an earthen bank and a shallow external ditch, or fosse. Its most telling feature, though, is not what survives of the bank but what was planted on top of it: the site was converted into a tree-ring, one of those deliberate circular plantings used by estate designers from the eighteenth century onward to punctuate parkland with ornamental groves. The question that lingers is whether the trees were planted around an ancient monument that was already there, or whether the whole thing, bank, ditch, and all, was constructed as a piece of landscaping from the outset.

The 1838 edition of the Ordnance Survey six-inch map shows the site as a grove of trees standing about 70 metres east of the main avenue leading to Clonyn House, suggesting that by that date the tree-ring function was well established. Ringforts, also known as raths, were circular or roughly circular enclosures built mainly during the early medieval period in Ireland, typically serving as farmsteads defended by earthen banks and ditches. If this earthwork is genuinely one of them, its bank and fosse would predate the estate by many centuries, and the post-1700 landscaping would represent a second life rather than an origin. Two further enclosures sit nearby, one about 45 metres to the north-east and another roughly 60 metres to the north-west, raising the possibility that all three were part of the same process, whether that means three ancient ringforts absorbed into a designed landscape, or three purpose-built ornamental features that simply resemble them. Tree stumps recorded on the site pointed toward the former interpretation, though aerial photographs taken in November 2011 show those stumps are no longer visible, leaving the ground itself as the only remaining witness to whichever story is true.