The souterrain at Keeas, an underground stone-built structure of the kind commonly associated with early medieval settlement in Ireland, does not appear on Ordnance Survey maps, and was blocked up sometime in the 1960s. What survives is largely in local memory: a drystone construction, the walls built without mortar, with steps descending into a covered passage below ground. Souterrains were typically used for storage or refuge, their cool, dark interiors suited to keeping food, or to sheltering people in times of danger.

The field where it lies is known as Gort na hÓn, a name recorded by Ó Cíobháin in 1978. The souterrain sits at the edge of a level terrace, an area of relatively flat ground before the land drops away steeply southward toward the river. That particular setting, a flat shelf on otherwise uneven terrain, is the kind of detail that can speak to how and why a site was chosen: close to water, on manageable ground, but with a natural slope offering some shelter and drainage. The Iveragh Peninsula, on which Keeas sits, is densely layered with early archaeological remains, and structures like this one are not rare in the broader landscape, though individually they are easy to overlook, especially when they carry no marker and are absent from official maps.