A circular enclosure roughly 55 metres in diameter was recorded on the Ordnance Survey six-inch map of 1842, marked with a dotted line that suggests the surveyors themselves were working from traces rather than solid earthworks. Today, the ground shows nothing at all. The site lies on a north-facing slope given over to pasture, and there is no visible surface feature to indicate that anything of significance ever stood here.

The dotted-line convention on early Ordnance Survey maps was typically used to indicate features that were already degraded or uncertain at the time of survey, meaning that even in the 1840s this enclosure was something the cartographers noted with a degree of caution. Circular enclosures of this kind in Ireland are most commonly associated with ringforts, the enclosed farmsteads of the early medieval period, though without excavation it is impossible to say with any confidence what this particular feature was, when it was built, or who used it. A diameter of around 55 metres falls within the typical range for such monuments. The placename element "Doon" is itself derived from the Irish "dún", meaning a fort or fortified place, which may suggest a local memory of some kind of enclosure here, even if the physical evidence has long since vanished beneath the grass.