A souterrain is an underground stone-lined passage or chamber, constructed during the early medieval period and used variously for storage, refuge, or both. This one was filled in before it could be properly examined, leaving behind little more than a memory and a brief note in a survey file.

The discovery, if it can be called that, happened sometime around 1956 to 1961, when a local landowner came across steps leading down into a small underground space. His own interpretation was practical rather than archaeological: he believed the chamber had been used for storing butter. This was not an unreasonable reading. Cool, dark underground spaces were well suited to preserving dairy produce, and souterrains across Ireland were indeed put to such domestic use during and after the medieval period, long after their original function had been forgotten. By the time the Castleisland District Archaeological Survey documented the site in 1986, the landowner confirmed that the area had since been filled in. The relationship to Currans Castle nearby adds a layer of interest, since souterrains are more commonly associated with ringforts and early settlement activity than with later tower house structures, though the proximity may simply reflect the long continuity of occupation at a single favourable location.