A shallow depression in the earth is the only visible sign, a gentle dip in the surface that could indicate the presence of an underground passage below, or could simply be the land settling in on itself over centuries.

A souterrain is a man-made underground structure, typically a stone-lined passage or chamber, built during the early medieval period in Ireland. They are found associated with ringforts and cashels, the latter being a stone-walled enclosure of the kind that survives at Caherkeegane. Their precise function has long been debated; they may have served as places of refuge, cool storage for food, or both. The cashel at Caherkeegane carries its own separate record, and this possible souterrain sits within its south-eastern quadrant, its exact nature unconfirmed. What remains is essentially a question mark pressed into the ground, a depression that invites interpretation without quite resolving into certainty.