The label is deceptively modest. What it indicates is a souterrain, an underground stone-lined passage of early medieval origin, typically associated with Irish ringforts and cashels and thought to have served as storage space, a refuge, or both. This one sits near the centre of a cashel, a type of stone-walled enclosure that would once have enclosed a farmstead or small settlement, and its position at the heart of that enclosure rather than along its margins is itself a detail worth noting.

The passage runs roughly north to south, stretching 5.5 metres in total length. Four stone lintels, large flat slabs laid across the top to form a roof, cover the central section, while the northern end (1.2 metres) and the southern end (0.35 metres) are unroofed. The interior is largely choked with stone, but where it can be seen, the construction reveals an unusual asymmetry: the east side appears to be cut directly into bedrock, while the west side is built up with a vertical wall of smaller stones. The visible interior stands roughly 1.7 metres high and between 0.8 and 0.9 metres wide, dimensions that suggest a crouching rather than upright passage. That combination of rock-cut and dry-stone walling in a single structure points to a builder working practically with what the ground offered, adapting technique to terrain rather than following a single method throughout.