A souterrain, for those unfamiliar with the term, is essentially a dry-stone lined tunnel or series of chambers constructed beneath ground level, typically associated with a nearby settlement or ringfort. They were used variously for storage, refuge, or as escape routes, and their cool, stable interiors made them practical for keeping foodstuffs through warmer months. The one at Elmhill is recorded as a monument, which confirms its existence in the archaeological register, though the particulars of its construction, dimensions, and condition remain unpublished for now.

Beyond its classification and location, the documented detail currently available for this site is sparse. What can be said is that souterrains of this type generally date to somewhere between the seventh and twelfth centuries, and they tend to cluster in areas of early agricultural settlement. Galway has its share of them, scattered across townlands that saw continuous occupation from the early Christian period onward. Without excavation records or a detailed field description for Elmhill specifically, it is not possible to say how many chambers it contains, whether it retains its original roofing lintels, or what condition the passage is in today.