A depression in the earth exposes a large, flat stone slab, and a patch of lighter-coloured grass grows nearby, the kind of subtle discolouration that can signal a void or disturbed soil beneath. Taken together, these are quiet signs of something hollow underneath.

What lies below is almost certainly a souterrain, an underground stone-lined passage or chamber built during the early medieval period, typically associated with ringforts. Souterrains were constructed for a variety of purposes, most likely cold storage and refuge, and were built to be discreet by design. The one at Cloghane remains largely unexcavated and unconfirmed in its extent. When the ground was probed, a second stone slab was detected behind the first, suggesting the structure continues further into the interior of the ringfort than the surface depression alone would indicate. How far it extends, and what form it takes, remains unknown.