Souterrains are underground stone-lined passages or chambers, typically built during the early medieval period and associated with ringforts, the circular earthen enclosures that once served as farmsteads across Ireland. They are thought to have been used for storage, refuge, or both. This one is particularly elusive: despite being recorded decades ago, it has left no visible surface trace whatsoever.

The record of its existence comes from Bowman, writing in 1934, who noted two souterrains within this fort and remarked that they "could easily be opened" at the time. That casual confidence, the sense that these passages were simply there, waiting, makes their current invisibility all the more striking. Whether they were subsequently opened, examined, or simply forgotten is unclear. The ringfort they sit within, though a separate monument, presumably still holds them somewhere below, undisturbed or at least undocumented in any detail that has since come to light.