The existence of this underground passage is a matter of local reputation rather than confirmed record, its precise location unascertained. That combination, a probable presence and an uncertain position, places it in a curious category of archaeological sites: known enough to be catalogued, elusive enough to remain genuinely mysterious.

A souterrain is a man-made underground structure, typically comprising stone-lined passages or chambers, and in Ireland these features are most commonly found in association with raths, the circular earthwork enclosures that served as farmsteads during the early medieval period. Their purpose is still debated; they may have provided storage, refuge, or ventilation, and likely different examples served different functions. The rath at Lisbane would have been the kind of enclosed settlement that once dotted the Kerry landscape in considerable numbers. The souterrain associated with it was noted in A. O'Sullivan and J. Sheehan's archaeological survey of the Iveragh Peninsula, published by Cork University Press in 1996, where it is recorded on the basis of local information alone, with no confirmed coordinates for the underground element itself.

That a souterrain should be known locally but not pinned down archaeologically is not as unusual as it sounds. Such features often survive as folk memory, a story about a tunnel beneath a field, passed down without documentation, sometimes accurate and sometimes embroidered over generations. The rath that contains it, or is said to, offers at least a fixed point in the landscape, even if what lies beneath remains a matter of reasonable speculation.