The chamber runs north to south for more than three metres, constructed in drystone, meaning the walls were laid without mortar, each stone held in place by weight and careful arrangement alone. It is, for now at least, inaccessible; the opening at the northern end offers a glimpse rather than an entrance.

The structure is a souterrain, an underground or semi-underground chamber of the kind built throughout early medieval Ireland, typically beneath or within a rath, the circular earthwork enclosure that was the standard farmstead of the period. Their purpose has long been debated: storage, refuge, ventilation for a dwelling above, or some combination of all three. This example sits at the centre of its associated rath, a placement recorded by McCaffrey in 1952. The combination of the earthwork and its subterranean chamber represents a fairly complete picture of how these sites were organised, even if the souterrain itself remains closed off to direct inspection.