That combination, oral tradition backed by lived experience rather than excavation or documentation, puts this site in a peculiarly Irish category: places that exist more in communal memory than in the archaeological record.

A souterrain is an underground stone-lined passage or chamber, typically associated with early medieval ringforts and used variously for storage, refuge, or ventilation of livestock areas. The one at Tullyneasky is linked to the ringfort recorded nearby, and local tradition holds that the tunnel was entered by people in the area at some point in the relatively recent past. No formal investigation appears to have followed, and the entrance, if it was ever clearly visible, has since become less obvious. A small hollow in the south-western part of the site is thought to mark the approximate position, the kind of subtle ground subsidence that often signals a roofed underground structure slowly giving way beneath the surface.