It was recorded, catalogued, and then, in a manner that says something quietly unsettling about the landscape, never actually found. The site at Derreen belongs to a category of place that is perhaps more common than people realise: archaeological features whose paper existence is confident and whose physical existence is, at present, unconfirmed.

Circular enclosures in Ireland are most often the remains of ringforts, the enclosed farmsteads that served as the basic unit of rural settlement from roughly the early medieval period onwards. Thousands survive across the country in varying states of preservation, and thousands more have been lost to ploughing, development, or simple neglect. At Derreen, the enclosure visible to the nineteenth-century surveyors who produced the first-edition OS map has since been swallowed by dense commercial forestry. When field surveyors working on the archaeological survey of South Kerry, published by Cork University Press in 1996, went to investigate, the plantation had done its work thoroughly enough that the feature could not be relocated on the ground. Whether the underlying earthwork survives beneath the trees, or whether decades of forestry activity have disturbed or destroyed it, remains an open question.