A collapsed area of earth, unremarkable to the untrained eye, points to something beneath: a possible souterrain, one of those stone-lined underground passages or chambers built during the early medieval period, typically serving a ringfort as a place of refuge, storage, or concealment.

Ringforts, the circular enclosures defined by earthen banks or stone walls that dot the Irish countryside in their thousands, were the farmsteads of early medieval Ireland, occupied roughly between the fifth and twelfth centuries. Many contained souterrains, which were constructed from dry-stone walling and roofed with large capstones, then buried under the ground. Over centuries, when the roofing stones shift or collapse, the surface above can sink or hollow, leaving exactly the kind of depression recorded at Cloonareague. The site sits within the northern portion of the ringfort, and while no excavation appears to have confirmed the souterrain's presence, the collapsed ground remains a credible indicator that something structured lies below.