A souterrain is an underground stone-lined passage or chamber, typically associated with early medieval settlement in Ireland, used for storage, refuge, or both. This one came to light not through archaeological excavation but through the entirely ordinary business of digging foundations for a shed. Once uncovered, it was filled back in immediately, and the ground closed over it again as though nothing had happened.

The episode is brief but telling. No excavation was carried out, no formal record was made at the time, and what survives is local knowledge rather than documentation: someone remembered, and the memory was eventually noted. The souterrain at Cashloura is known to exist only because word of it passed along. There is no visible surface trace whatsoever, which means the site itself offers nothing to the eye, only the knowledge that something is down there, sealed back into the earth a little over fifty years ago.