That spatial relationship, deliberate and slightly uncanny, is what sets the souterrains at Barnageeragh apart from a routine archaeological find. Souterrains are stone-lined or rock-cut underground passages and chambers, typically associated with early medieval settlement in Ireland, and generally interpreted as places of refuge, storage, or both. Finding a pair of them arranged in this way is less common.

The two souterrains came to light not through dedicated research but through the kind of rescue archaeology that precedes development work, carried out under excavation licence 06D0477. The western souterrain, recorded by Corcoran in 2009, had a circular chamber at its core, with a small pit cut into the floor, the purpose of which is not recorded in the available notes. From that chamber, a main passage ran to the northeast before changing direction to the southeast, leading eventually to the entrance. The eastern souterrain, described as similar in character, mirrored it across the site. The precise early medieval context and the wider settlement of which these features formed a part were not fully published in the available record.

Barnageeragh is in north County Dublin, and given that these souterrains were excavated ahead of development, the physical structures are unlikely to be accessible or visible today. Sites of this kind are rarely preserved in situ when discovered in such circumstances, the recording and publication of the findings being the primary form of survival. Anyone interested in the archaeology of the area would do better to seek out Corcoran's 2009 report, which contains the detail gathered during excavation, rather than expecting anything to see at ground level. The value here is in the documented record of how two people, at some point in the early medieval period, built two mirroring underground passages and arranged them so their doors faced one another.