At Crannagh in County Galway, the Ordnance Survey's 1838 six-inch map marks a feature called "Caves" sitting within the interior of a rath, the kind of circular earthwork enclosure that served as a farmstead in early medieval Ireland. By the 1922 edition the name had contracted to the singular "Cave", but the spot was still deemed worth recording. Now, no visible surface trace survives at all.

The association with a rath is quietly telling. These enclosures, typically defined by an earthen bank and ditch, occasionally contained souterrains, which are artificial underground passages built from stone, used for storage or as places of refuge. Whether what the early mapmakers called "Caves" referred to a natural hollow, a souterrain, or something else entirely is no longer clear. The site sits within a broader landscape that the nineteenth-century surveyors were carefully documenting, and their decision to assign a placename to this particular feature suggests local knowledge of something worth distinguishing. That knowledge, and whatever physical form once gave rise to it, has since been lost to time or ground disturbance.