The opening measures roughly forty centimetres across and forty centimetres high, partially blocked by loose stones, and it leads down into something older and more deliberate than it first appears.

What lies below is a souterrain, an underground passage of dry-stone construction roofed with flat lintels, the stones laid without mortar and relying on careful placement alone. The passage widens once inside, running somewhere between eighty-five and ninety centimetres across, and it extends northward into the ground. Souterrains are found across early medieval Ireland, typically associated with raths, the circular earthwork enclosures that served as farmsteads during the first millennium and into the early centuries of the second. They are thought to have functioned as places of refuge, cool storage for dairy produce, or both. This particular example sits slightly north of centre within its rath, a positioning that suggests it was integral to the original plan of the enclosure rather than added as an afterthought.