The only account of it comes from local information describing something curious: an opening, resembling a sunken well, fitted with a covering stone. That description alone is enough to suggest one of Ireland's more quietly persistent archaeological features, a souterrain being an underground passage or chamber, typically built during the early medieval period and associated with ringforts, used variously for storage, refuge, or both. At Lisheen, even that modest trace has since disappeared. There is no visible surface evidence remaining.

The souterrain sits within, or rather beneath, a ringfort recorded in the Cork Sites and Monuments record. Ringforts were enclosed farmsteads, usually circular, defined by one or more earthen banks and ditches, and they were built in their thousands across Ireland between roughly the fifth and twelfth centuries. It was common practice to excavate souterrains within them, the underground spaces offering a cool, dark environment for dairy produce and, when necessary, a place to shelter. At Lisheen, the pairing of ringfort and souterrain fits a well-established pattern, even if the physical remains of the souterrain itself have left nothing to see at ground level. The description of an opening like a sunken well with a covering stone suggests the entrance survived long enough to be noticed and passed on as local knowledge, before it too was lost or obscured.