A souterrain is a deliberately constructed underground chamber or tunnel, typically dry-stone built, dating in Ireland most commonly to the early medieval period between roughly the seventh and twelfth centuries. They are found across the country in their hundreds, often associated with ringforts and farmsteads, and their precise purpose has long been debated: cold storage, refuge, or both. The one at Clogherrevagh is recorded but, for now, tells its story quietly.

Beyond its place-name and county, the available detail on this particular site is thin. Clogherrevagh, like many Irish townland names, likely derives from a compound involving "clochar," referring to a stony place or a stepping-stone ford, though the specifics of this souterrain, its dimensions, its state of preservation, and any associated surface features, remain to be fully set out in accessible form. What can be said with confidence is that souterrains in Connacht, the province in which Sligo sits, follow broadly the same constructional traditions as those elsewhere in Ireland, with corbelled or lintelled roofs, narrow crawl-through passages, and occasional right-angle turns that may have served as defensive chicanes. The presence of one at Clogherrevagh places this quiet corner of Sligo within a wider early medieval landscape that was far more densely settled and organised than the empty fields might now suggest.