Measuring thirteen metres long and just over half a metre deep, it traces the outline of something that may once have run underground, a collapsed souterrain, the kind of stone-lined tunnel that early medieval farmers built beneath their homesteads for cold storage, refuge, or both. The collapse of the roof has left the ground above it slightly sunken, a faint negative impression of a structure that has not been visible for perhaps a thousand years.

The enclosure itself is a rath, the most common monument type in the Irish landscape, built during the early medieval period, roughly between the fifth and twelfth centuries, as a defended farmstead for a single family or small household group. This particular example sits on a west-facing slope in pasture, and its dimensions are reasonably substantial: just under forty-seven metres across in one direction, forty-six in the other. The boundary is formed by a low earthen bank, still standing nearly a metre high on the interior face, with an external fosse, a dug ditch, preserved along the south-east arc. Elsewhere the enclosure edge relies on a scarped slope, where the ground has simply been cut back to create a natural-looking but deliberately engineered boundary. The interior tilts gently downward to the west, following the natural lie of the hillside.