A souterrain, to use the technical term, is an artificial underground structure, typically built during the early medieval period in Ireland, consisting of one or more chambers connected by low crawlways and constructed from dry-laid stone. They are found across the country in considerable numbers, often associated with ringforts or early settlement sites, and their purpose has been debated for generations. Theories range from food storage, where the constant cool temperature would have been useful, to refuges in times of attack, to simple concealment of valuables. The one at Clogher has attracted little public attention, which is itself a kind of curiosity.

The Clogher townland sits in a part of Mayo where early medieval activity left its marks on the landscape in various forms, and souterrains in the west of Ireland frequently turn up in association with the traces of enclosures or field systems that have long since been absorbed into the agricultural ground. Without detailed excavation records available for this particular site, the precise date of construction and the nature of any associated settlement remain open questions. What is known is that the monument has been recorded and classified, placing it within a broader pattern of underground architecture that Irish communities were building and using from roughly the seventh century onwards, continuing in some areas into the twelfth.