It is a souterrain, a type of man-made subterranean structure built during the early medieval period in Ireland, typically constructed from drystone walling and roofed with large flat lintels. They are found across the country in considerable numbers, often associated with ringforts or settlement sites, and their precise function has long been debated. Refuge, cold storage, and concealment have all been proposed, and the honest answer is probably that they served more than one purpose depending on circumstance.

The souterrain at Curry is recorded as a monument, though the finer details of its construction, dimensions, and immediate archaeological context remain to be more fully documented. What is known is that Mayo has a respectable tradition of such structures, frequently turning up in the course of agricultural work or field survey, sometimes intact and sometimes partially collapsed. The early medieval communities who built them were farming the same landscape, and the underground world they created was a deliberate and skilled piece of engineering, not a casual excavation. Stones were carefully selected and placed, passages were occasionally subdivided into chambers, and some souterrains include deliberately low or narrow sections that would slow any intruder considerably.