Souterrains are underground stone-lined passages or chambers, constructed during the early medieval period, typically between the seventh and twelfth centuries. They are found across Ireland in their hundreds, usually associated with ringforts or settlement sites, and their exact purpose remains a matter of some debate among archaeologists. Theories range from food storage, where the stable underground temperature would have been useful, to refuges in times of threat, or simply as drains. The one at Lissodeige carries no publicly available detail beyond its existence and its location, which lends it a particular kind of obscurity, the sort that belongs to places known to the record but not yet legible to the curious outsider.

Without accessible documentation, the specific circumstances of this souterrain, when it was discovered, by whom, what form it takes, whether it is a simple passage or a more complex arrangement of chambers, remain unknown from the public record. What can be said is that Kerry is not short of such structures. The county's landscape of ringforts and early Christian settlements has yielded many underground features over the years, some stumbled upon during agricultural work, others identified through aerial survey or ground investigation. Lissodeige itself is a quiet rural townland, and the souterrain sits within it as an unelaborated fact, a coordinate and a classification without a story yet attached.