The word undersells what is actually there: a souterrain, an underground passage and chamber of dry-stone construction built beneath an early medieval earthwork, where a person would once have had to drop to their hands and knees to move between spaces. Souterrains, found across Ireland and often associated with raths or ringforts, were typically used for storage, refuge, or both, their cool interiors keeping dairy produce at a steady temperature and their narrow creeps making armed pursuit nearly impossible.

This particular souterrain sits in the northern half of a rath, the circular earthen enclosure that was once somebody's farmstead, likely dating to the early medieval period. The structure is roughly L-shaped in plan. A collapsed opening in the interior of the rath leads into a passage running north-north-west, about eight metres long, seventy centimetres wide, and just over a metre high; enough to crouch through, no more. The walls lean gently inward as they rise, supporting a roof of flat slabs. Partway along, a tight creep in the northern wall, only sixty centimetres wide and ninety centimetres high, opens into a small corbelled chamber, where the roof is formed by overlapping stones drawing inward to a close, a technique requiring no mortar and considerable skill. That chamber is about one and a half metres high at its tallest point, and it extends partly beneath the bank of the rath itself. A third passage once ran westward from the chamber, following the inner edge of the bank for around eleven metres, but it is now collapsed and visible only as a long grassy depression in the ground. Local memory holds that the stones were taken away at some point to build farm buildings nearby, a fate common to many structures that stopped serving their original purpose and started looking like a convenient quarry.