It sits in the south-eastern corner of an old cashel, a type of stone-walled enclosure associated with early medieval settlement in Ireland, pressing up against the interior face of the wall. It measures roughly 8.5 metres at its widest and rises only about half a metre from the ground. Unassuming by any measure, it has nonetheless resisted classification. Its function, in the careful phrasing of archaeological record, is simply not clear.

The site is known as Lissonenakilla, or Lios an Anacail in Irish, and the cashel itself is roughly oval in plan. At its centre stands a clochán, a small dry-stone corbelled structure of the kind found across the Dingle Peninsula, typically associated with early Christian monastic activity or agricultural use in the early medieval period. The clochán and the cashel wall together form a coherent, if modest, complex. The mound in the south-east quadrant is the odd element. It could be a collapsed structure, a burial, a storage feature, or something else entirely. The 1986 Dingle Peninsula archaeological survey compiled by J. Cuppage recorded it without offering a conclusion, and subsequent research has not resolved the question.

That unresolved quality is perhaps what makes the site genuinely interesting. The Dingle Peninsula is dense with early medieval remains, and most of them can at least be tentatively categorised. A feature that simply sits there, abutting an ancient wall, defying tidy interpretation, is rarer than it might seem.