The structure belongs to a category of underground feature commonly called a souterrain, a type of drystone-built tunnel associated with early medieval settlement in Ireland, typically thought to have served as a place of refuge, storage, or both. What makes this example quietly interesting is how complete its basic form remains, dimensions, orientation, and even a possible air vent at its eastern end, all still legible despite its age.

The passage runs on an east-north-east to west-south-west axis and measures just under five metres in length, with a width of roughly one and a half metres and a ceiling height of about the same. It sits within a cashel, a term for a roughly circular stone-walled enclosure that typically defined a farmstead or small defended settlement during the early medieval period in Ireland. The relationship between the souterrain and the cashel it belongs to is typical of the period; souterrains are frequently found built into or beneath the walls and interiors of such enclosures across Connacht and beyond. Entry to this particular passage is possible through the gap left by the displaced lintel stone near its western end, and what appears to be a ventilation opening survives at the eastern end, a detail that hints at deliberate design rather than simple utility.