The far end is blocked, a narrow creepway marks the limit of what survives accessible, and the whole thing measures less than four metres from end to end. There is nothing obviously dramatic about the dimensions, yet that compression is rather the point. Souterrains, the dry-stone underground passages built in early medieval Ireland, were not meant to impress from the outside. They were functional, discreet, and deliberately inconspicuous, associated typically with the enclosed farmsteads called raths, the circular earthwork settlements that once organised much of the Irish rural landscape.

This particular passage is stone-built and lintelled, meaning flat capstones were laid across upright side walls to form a roof, a construction technique common to souterrains across Ireland and Scotland. It runs roughly northwest to southeast, stands about 0.9 metres high, and is 0.8 metres wide on average, dimensions that would require an adult to crouch or crawl. At the northwest end, a section of coursed walling survives, and this is thought to represent the original point of entry, the place where someone would have descended from the rath above. The southeast end narrows into a creepway, a deliberately tight constriction of the kind often found in souterrains, possibly designed to slow an intruder or simply to mark the transition to a chamber that is now completely blocked. A. O'Sullivan and J. Sheehan documented the structure as part of a thorough archaeological survey of the Iveragh peninsula published by Cork University Press in 1996, placing it within a wider landscape of early medieval settlement across south Kerry that is considerably denser than the region's later history might suggest.