A local tradition holds that a souterrain, an artificially constructed underground chamber or tunnel typically built during the early medieval period and associated with nearby ringforts, once had its opening just outside the south-south-west bank of the ringfort at Ardkitt. Whether that opening has collapsed, been deliberately filled, or simply been swallowed by centuries of agricultural activity, the ground today gives nothing away. There is no visible surface trace whatsoever.

The ringfort to which this souterrain belongs, recorded as CO109-078, would have been a farmstead enclosed by an earthen bank, a common form of rural settlement in Ireland from roughly the fifth to the twelfth century. Souterrains were frequently dug in association with such enclosures, serving variously as places of refuge, cool storage for foodstuffs, or concealed escape routes. That one was traditionally believed to exist at Ardkitt is notable in itself, even if its precise location and condition remain unknown. Oral tradition has a reasonable record of preserving knowledge of underground features long after any physical evidence has vanished at the surface, so the account is not easily dismissed.