A souterrain is an underground stone-lined tunnel, usually dating to the early medieval period in Ireland, built for purposes that archaeologists still debate: food storage, refuge, or a combination of both. This particular example is mapped simply as "Cave" on the second edition of the Ordnance Survey, which suggests that by the time the surveyors arrived, living memory of its original purpose had already faded into something more elemental and less precise.

The structure consists of two short passageways joined by a creepway, a narrowed connecting section low enough to force a person to crouch or crawl, a feature common in souterrains and thought to have served a defensive function. Built entirely of stone, it sits within the woodland of Faha on the Iveragh Peninsula, that long arm of south Kerry that reaches into the Atlantic. The souterrain became waterlogged at some point and was infilled during the 1970s, according to local knowledge, effectively ending any prospect of direct access or straightforward excavation. It is catalogued in A. O'Sullivan and J. Sheehan's archaeological survey of the Iveragh Peninsula, published by Cork University Press in 1996, which remains one of the more thorough regional surveys of its kind.

The site is not accessible, and the infilling means there is nothing visible to a visitor who might go looking. What remains is the outline of the thing: a forgotten tunnel mapped under the wrong name, quietly recorded, then quietly buried again.