No depression in the ground, no tell-tale hollow, no exposed stonework gives it away. It simply sits in the record, unverified and invisible, a gap in the earth that may or may not be there.

A souterrain is an underground stone-lined passage or chamber, typically built during the early medieval period and associated with settlement sites. They were used variously for storage, refuge, and ventilation, and they appear in their hundreds across Ireland, often beneath or beside ringforts. A ringfort, to give the briefest explanation, is a circular enclosure defined by one or more earthen banks and ditches, the standard farmstead form of early medieval Ireland. The ringfort at Dunowen is recorded separately, and it is within or immediately alongside that enclosure that the souterrain is said to lie. The attribution rests entirely on local tradition rather than excavation or physical survey, and no surface trace has ever been confirmed.