At Toorboney in mid Cork, a shallow depression sitting just west of centre within a ringfort is the probable signature of a souterrain, an underground passage or chamber built, typically in the early medieval period, beneath or beside a defended settlement. These stone-lined underground structures served various purposes, most likely food storage, refuge, or both, and their presence within a ringfort is a relatively common but always intriguing combination.

The ringfort itself, a circular enclosure defined by earthen banks and ditches and one of the most characteristic monument types in the Irish landscape, forms the immediate context here. Souterrains within such enclosures were usually constructed by corbelling stone or lining earth-cut tunnels, and their roofs, when unsupported by later maintenance or sheer luck, are prone to collapse over the centuries. What the ground at Toorboney now shows is most likely that collapse, a sunken hollow where a chamber once held its shape underground. The word "possible" in the description matters; without excavation, the depression remains suggestive rather than confirmed.