At Knockearagh in County Kerry, local tradition holds that a souterrain once existed within a rath, yet no visible trace of it remains today. A souterrain is an underground stone-lined passage or chamber, typically associated with early medieval settlements in Ireland, often used for storage or concealment. That one may have existed here is taken seriously enough to be recorded, but the ground keeps its own counsel.

The souterrain sits, at least in memory, within a rath, which is a roughly circular earthen enclosure that served as a farmstead during the early medieval period, roughly 500 to 1200 AD. Raths are among the most common archaeological monuments in Ireland, and many once contained souterrains accessible from within the enclosure. At Knockearagh, local information suggests the passage was closed a long time ago, though no documentation survives to explain when or why. The phrasing "possible souterrain" reflects the careful position of archaeologists working from oral tradition alone, without physical evidence to confirm the structure.

There is nothing to see at this site in any conventional sense. The rath itself is recorded separately, but the souterrain has left no surface trace whatsoever. What the Knockearagh entry quietly illustrates is how much of the Irish archaeological landscape survives only in local memory, passed down through generations and eventually caught, just in time or perhaps too late, in the net of a formal survey.