A souterrain, to use the archaeological term, is an artificial tunnel or chamber built into the earth, typically during the early medieval period in Ireland, roughly between the seventh and twelfth centuries. They were constructed from dry-stone walling and roofed with large stone lintels, then buried. Depending on the site, they served as places of refuge, cool storage for food, or both, and they are found across Ireland in their hundreds, most often associated with the ringforts and farmsteads of the period.

The townland name Lisnamoltaun hints at exactly this kind of settled, enclosed landscape. The element "lis" refers to a ringfort, an enclosed circular farmstead of the early medieval period, and the presence of a souterrain in such a townland would fit a very familiar pattern across the Irish countryside, where underground passages were dug to adjoin or lie beneath the domestic enclosure above. Beyond its classification and location, the specific details of this particular souterrain, its dimensions, its state of preservation, when it was first recorded, and by whom, remain publicly unverified for now.