Discovered in 1981, the structure is a souterrain, an earth-cut underground passage or series of chambers associated with early medieval Irish settlement, typically used for storage, refuge, or both. What makes this particular example notable is its scale and the deliberate geometry of its layout: six chambers arranged at right angles to one another, each connected by narrow creepways through which a person would have had to crawl.

The chambers vary considerably in their dimensions, ranging from the largest at 4.3 metres long down to a modest 2 metres, and the ceiling heights in several drop to just 0.8 metres, making them uncomfortably tight by any standard. The whole network includes an annexe at the north-north-east end of the first chamber, and construction shafts were identified in the annexe and in four of the six chambers. These shafts, sunk from above during the building process, would have allowed excavated soil to be removed and materials to be lowered in, then presumably sealed once the work was complete. Chamber four may have served a different function from the others, containing what appears to be a possible air vent rather than a construction shaft. Two separate entrance points were also identified: the original entrance at chamber five, and a possible second entrance at chamber six. The excavation was documented by Cleary in 1981, providing the detailed record from which all subsequent descriptions of the site derive.

The engineering logic of the place rewards attention even on paper. Building six interconnected underground rooms by hand, at angles to each other, with dedicated construction access points, represents a considerable effort, one that implies the settlement it served was substantial enough to justify it. The low ceiling heights in particular suggest these spaces were designed for function rather than comfort, and that whoever used them understood the difference.