The structure is a souterrain, an underground tunnel or chamber built from drystone, the technique of fitting stones together without mortar, and it sits almost completely blocked, its existence announced only by a small gap in the roof through which the outline of a passage can just be glimpsed. It runs on a northwest to southeast axis, though what it once connected, or sheltered, or concealed is no longer easy to say.

Souterrains are found across early medieval Ireland, typically associated with ringforts and used variously for storage, refuge, or ventilation of adjoining structures. This one, however, sits in curious isolation. By 1930 it had already been marked on the Ordnance Survey six-inch map, third edition, as a solitary feature with no obvious companion structure nearby. A local study by Neary, published in 1914, noted that the souterrain marks the site or proximity of a ravelled fort, meaning a fort whose fabric has been robbed out or otherwise dismantled over time, leaving no visible surface trace. The enclosure that once stood here, most likely a ringfort of some kind, has entirely disappeared into the landscape, leaving its underground element as the only surviving evidence that anyone organised the land in this way at all.

What remains is almost paradoxical: a subterranean feature that has outlasted the above-ground structure it was presumably built to serve. The passage is inaccessible, and there is nothing dramatic to see at the surface, just level ground sitting somewhat incongruously within otherwise hilly grassland. The gap in the roof offers the only view of the drystone construction beneath, a narrow glimpse of something that was built to be hidden, and has remained so.