It is a souterrain, a type of structure built during the early medieval period in Ireland, typically consisting of one or more corbelled or lintelled chambers connected by low crawlways and dug into the earth or constructed beneath field banks. Their purpose has long been debated, with theories ranging from cool-storage for dairy produce to places of refuge during times of raid or conflict, and most likely they served both functions at different times.

Carrowoughteragh is a quiet townland in the west of Mayo, and the souterrain recorded there represents the kind of monument that exists in its hundreds across Ireland, frequently on private farmland, occasionally disturbed by drainage or cultivation, and often known locally for generations before any formal record takes notice of them. The broader Mayo landscape contains numerous examples of early medieval settlement, and a souterrain in this area would fit a pattern of dispersed farming communities that characterised the Irish countryside from roughly the sixth to the twelfth centuries. Beyond its classification and location, the specifics of this particular structure, its dimensions, its current condition, and the circumstances of its discovery, remain unavailable in any accessible public record at present.