Nothing about its cartographic appearance suggests anything older lying beneath. Yet at the centre of the earthwork, a rectangular depression roughly five metres by eight metres, edged with loose stones, points to something that predates the planting scheme by a very long margin indeed.

The earthwork is, in origin, a ringfort, the circular or oval enclosed settlements that were built across Ireland from the early medieval period onward, typically housing a farming family and their livestock within a raised bank and ditch. Sometime after 1700, the occupants of Ballynascarry House, located about 770 metres to the east, appear to have repurposed this particular ringfort, planting trees around its perimeter to convert it into a fashionable landscape ornament. The practice was not uncommon among improving landlords of the period, who found that the ready-made circular earthworks made convenient and atmospheric tree-rings without the labour of constructing new ones. A second, similar tree-lined earthwork survives roughly 480 metres to the north, suggesting this stretch of ground was subject to the same deliberate aesthetic treatment. The rectangular stone-edged hollow at the centre of the fort may be the remains of a house that once stood inside the ringfort, though its precise date is uncertain. The site sits on a low north-south ridge with open views to the west and northwest, though higher ground closes in on the other sides.