A souterrain, to give the structure its proper name, is a type of subterranean chamber or tunnel constructed, typically in early medieval Ireland, by roofing over a trench with large stone lintels and then covering the whole thing back over with earth. They are found across Ireland in considerable numbers, often associated with ringforts or early settlement sites, and their purpose is still debated: cold storage, refuge, or perhaps some combination of both. The example at Carrowmoremoy is recorded as a monument, but detailed information about its dimensions, condition, or precise construction has not yet been made publicly available.

Without fuller documentation in circulation, the site remains one of those quiet entries on the archaeological map of Mayo, a county that contains a remarkable density of prehistoric and early historic remains. The townland name itself, Carrowmoremoy, derives from the Irish and suggests a placename of some descriptive character relating to the landscape, though the specifics of the souterrain, its date, its relationship to any nearby settlement, and its current state of preservation, remain to be properly set out in the public record.