The word "may" is doing real work here. There is nothing to see above ground, no hollow sound underfoot that a visitor could point to, no collapsed lintel poking through the soil. What survives is something more intangible: a local tradition, passed down orally, that an underground chamber exists within what is thought to be a rath.

A rath, sometimes called a ringfort, is a roughly circular enclosure defined by an earthen bank and ditch, the most common monument type in the Irish countryside and typically dated to the early medieval period, roughly the fifth to twelfth centuries. The rath at Derreenataggart is itself described only as a possible example, meaning the earthwork survives in some form but perhaps not clearly enough to be certain of its classification. Within such enclosures, souterrains were frequently constructed, and their locations were not always obvious even to those living nearby in later centuries. The tradition recorded here, of an underground chamber in the rath, fits a broader pattern across Ireland in which local memory preserves the knowledge of buried features long after the features themselves become invisible at the surface.