Roughly nine metres long, its axis running east to west, the rectangular depression sits inside a circular enclosure and is thought to be the remains of a souterrain, an underground passage or chamber of the kind typically built in early medieval Ireland for storage, refuge, or both. The ground above has long since collapsed or been levelled, leaving only the suggestion of what was once concealed beneath it.

The enclosure surrounding it is a rath, a type of ringfort defined here by two earthen banks with a fosse, or ditch, running between them. At thirty-four metres in diameter, it sits in fair condition on its hillock, which would have given its original occupants a clear view of the surrounding landscape. The inner bank still reads clearly on the western and northern sides, while elsewhere the ground simply scarps away to form the boundary. The outer bank is more fragmentary, though it holds its shape best to the south. A two-metre gap on the eastern side is considered original, meaning it is likely where the entrance once stood. Raths of this kind were the farmsteads of early Christian Ireland, occupied roughly between the fifth and twelfth centuries, and the presence of a souterrain within one is not unusual. What makes Moneyveen quietly arresting is the way the underground element has surfaced, literally, as a long, readable indent in the turf, hinting at a structure that was once carefully hidden and is now only legible because it has partially given way.