Nothing is visible on the ground to confirm or deny it. No hollow, no disturbed earth, no tell-tale depression marks the place where an entrance might once have been.

A souterrain, in the general archaeological sense, is a man-made underground passage or chamber, typically built during the early medieval period in Ireland as a place of refuge or cold storage, often associated with a nearby settlement or ringfort. The classification at Lackagh Beg carries an implicit question mark, however. A castle and the site of a Roman Catholic chapel are recorded in the same area, and their presence complicates the picture. The kilometre-long tunnel of local memory is far longer than any confirmed souterrain, which rarely extend more than a few tens of metres. Folklore has a habit of threading underground passages between notable landmarks, and castles and chapels are exactly the kind of landmarks such stories tend to connect. Whether the tradition preserves a distorted memory of a genuine early medieval structure, or whether it grew up around the castle and chapel and was later attached to the site as souterrain, is a question that cannot currently be answered from the surface.

There is nothing for a visitor to see at the site itself, which may be part of what makes it quietly interesting. The tradition survives without physical evidence to anchor it, passed along because the idea of a tunnel running beneath a kilometre of Galway farmland is simply too compelling to drop.