That phrasing, vague and tantalising in equal measure, is essentially the extent of what is formally recorded about this particular souterrain, and yet it captures something characteristic of these structures: they exist at the edge of certainty, half-remembered, half-found.

Souterrains are underground stone-lined passages or chambers, typically associated with early medieval ringforts in Ireland, and built for purposes that archaeologists still debate, most likely a combination of storage, refuge, and concealment. The one at Castlequin carries no excavation record, no measured plan, no confirmed entrance dimensions. What survives is local knowledge, the kind passed along in the same way the souterrain itself was probably used, quietly and without much ceremony. The Iveragh Peninsula, on which Castlequin sits, is dense with archaeological remains of this kind, and A. O'Sullivan and J. Sheehan's survey of South Kerry, published by Cork University Press in 1996, catalogued the site among hundreds of others across this stretch of southwest Ireland.