No hollow in the ground, no crop mark, no folklore attached to a particular stone had given the game away. The only reason anyone knows it is there at all is the accident of the blade catching that large flat stone and the cavity opening beneath it.

The structure is a souterrain, a type of underground passage or chamber built during the early medieval period, typically by corbelling or lining stone slabs to create a roofed tunnel. They are found across Ireland in considerable numbers, usually in association with ringforts, the circular enclosed farmsteads that were the dominant settlement type of early medieval Ireland. Ringforts themselves are often subtle features in the landscape, defined by an earthen bank and ditch, and the souterrain at Gormlee sits within one. Whether the chamber served for cold storage, as a place of refuge, or some combination of both is a question that applies to souterrains generally; this particular example has not been excavated, and its full extent remains unknown. What can be said is that someone in early medieval Gormlee went to considerable effort to construct something deliberately hidden, and that effort succeeded rather completely for a very long time.