The structure is a souterrain, an underground stone-lined tunnel typically associated with early medieval ringforts in Ireland, used variously for storage, refuge, or ventilation. What makes this particular example quietly compelling is not its scale but its specificity: the measurements recorded during excavation paint an unusually precise picture of a cramped, deliberate piece of construction tucked into the south-western corner of a ringfort.

The souterrain was excavated between 1934 and 1935 by Seán P. Ó Ríordáin, whose findings were published in 1940. When discovered, the passage was completely silted up, and the silting contained a notable quantity of decayed organic matter, which led Ó Ríordáin to conclude that the infill had accumulated during the active occupation of the fort rather than long after it was abandoned. The passage ran to approximately 27 feet, or 8.2 metres, in length. Along most of its course it was less than 2 feet wide, around 0.6 metres, though it widened at both the inner and outer ends to over 3 feet. The walls, standing to a surviving height of about 2.5 feet, were built from relatively small stones averaging around 8 inches across, with occasional larger blocks inserted among them, one measuring as much as 3.5 feet in length. The roof was absent when excavated; some of the original roofing slabs were recovered from the collapsed fill, but not enough to account for the full covering, suggesting that at least some slabs had been deliberately removed after the souterrain fell out of use. The floor sloped inward from the direction of the fort's centre, and the inner end was built directly into the ringfort bank itself, referencing catalogue number LI048-034025 in the national record.

The site sits within a ringfort, which is a roughly circular enclosure defined by an earthen bank and ditch, common across early medieval Ireland as a form of defended farmstead. The souterrain itself is no longer accessible in any conventional sense; what remains is an archaeological record rather than a visitor experience. Anyone with a serious interest in the site would do well to consult Ó Ríordáin's published report alongside the plans and orthoimagery available through the national monuments record. The surrounding landscape of east Limerick repays careful attention on its own terms, with the earthwork of the ringfort itself still visible on the ground and in aerial imagery.