It sits within the interior of a rath, one of the thousands of circular earthwork enclosures that dot the Irish countryside, typically dating from the early medieval period and used as defended farmsteads. The label suggests something underground, most likely a souterrain, a type of man-made passage or chamber built beneath or alongside such enclosures, often used for storage or refuge. What makes this particular spot quietly odd is the gap between what the map records and what the ground now shows: no visible surface trace of the feature survives at all.

By the time the Ordnance Survey teams were moving through Connacht in the 1830s, they were documenting features that local people clearly still recognised and named. The fact that this one was called "Cave" suggests it was a tangible presence in the landscape at that point, memorable enough to earn a label. Souterrains were sometimes still in use as cool storage spaces well into the post-medieval period, long after any memory of their original purpose had faded. Whatever existed at Cartron was noted, named, and then, somewhere in the intervening years, lost to view entirely, whether through collapse, deliberate filling, or gradual accumulation of soil and vegetation.