What makes this particular souterrain, discovered in April 1985, worth pausing over is a single peculiar detail: the passageway leading into its fifth chamber is not the usual low, lintel-roofed creepway found in these structures, but a circular opening roughly 70 centimetres wide that drops steeply downward. Souterrains, to give the general explanation its due, are man-made underground passages and chambers associated with early medieval settlement in Ireland, typically used for storage or refuge. Most follow a fairly consistent pattern of construction. This one does not, at least not entirely.

The structure comprises six earth-cut chambers in total, as recorded by Cleary in 1989. Three of them, chambers 1, 3, and 4, are rectangular in plan; the remaining three are irregular in shape, which itself is not extraordinary, but when combined with the unusual circular drop into chamber 5 and the presence of construction shafts in both chambers 5 and 6, the overall picture is of something built with more complexity than the typical example. A lintelled creepway on the north-east side of chamber 1 is thought to be the original entrance, and a second creepway on the south side remains inaccessible and may connect to chambers as yet unexamined. On the floor of chamber 6, numerous rat bones were recovered, though these were dated to the medieval period and later, placing them well after the souterrain's original construction and use.