The outline of an ancient circular enclosure survives not as visible earthworks but as a cropmark, a phenomenon that occurs when buried features such as ditches cause the vegetation above them to grow differently from surrounding soil, creating patterns that only become legible from the air.

The enclosure was identified from an aerial photograph, reference GB91.EH.19, which revealed a circular form defined by a fosse, the term used for a ditch dug as a boundary or defensive feature around an enclosed area. Such circular enclosures are among the most common archaeological monument types in Ireland, often associated with early medieval settlement, though the precise date and function of this particular example at Baunmore has not been established from the available evidence. What the aerial image captures is the fosse itself, its line preserved underground long after whatever stood within the enclosure has disappeared from view entirely.