A souterrain, from the French for "underground way", is a type of early medieval tunnel or chamber, typically built from dry-stone walling and roofed with large flat lintels, and associated with nearby settlement enclosures. This one lies roughly 45 metres to the east-north-east of a cashel, a type of stone-walled ringfort enclosure, the two structures almost certainly connected in origin and function.

When the site was inspected in April 1967, the picture inside was a dispiriting one. Some of the roof lintels had already been robbed out, probably taken for use elsewhere on the farm, and the interior had been packed solidly with field-clearance stones, the kind of material farmers routinely shift off land being brought into productive use. The structure may be the same souterrain catalogued by McCaffrey in 1952, where it appeared as entry number 50 in what was evidently an early survey of antiquities in the area. Whether it was already in poor condition by then is not recorded, but the gap between that documentation and the 1967 inspection suggests the damage occurred somewhere in those intervening years, or perhaps long before either visit.