Aerial photographs taken in August 1996 show the feature as a cropmark, that telltale variation in crop colour and growth that occurs when buried features alter how moisture and nutrients move through the earth above them. The enclosure measures roughly 50 metres across on its north-west to south-east axis and stretches to about 65 metres overall on the north-east to south-west line, making it a substantial oval by any measure.

What is particularly interesting about this site is the category it falls into. The second edition six-inch Ordnance Survey map records it as a tree-ring, a term used for a circular or oval plantation of trees, usually laid out as part of a designed landscape around a country house or estate. These plantings were common features of eighteenth and nineteenth century estate management in Ireland, serving both an ornamental purpose and, in some cases, a practical one as shelter belts or visual punctuation in a landscaped demesne. The trees themselves are long gone at Dunmore Park, but the root disturbance and buried organic material they left behind continues to influence what grows in the field above. The western portion of the enclosure crosses into an adjacent field, where the cropmark fades, though aerial photography suggests a subtler darkening of the soil in that area, hinting that the full oval shape is intact beneath the surface.