It may be all that remains of a souterrain, an underground stone-lined passage or chamber built during the early medieval period, typically used for storage, refuge, or ventilation within a settlement. The hollow's shape is suggestive, but collapse over centuries has left it ambiguous, somewhere between a definitive archaeological feature and a landscape that has simply forgotten what it once was.

The ringfort with which this feature is associated sits on flat to undulating ground in Breeoge, County Sligo, close to the shores of Ballysadare Bay. Ringforts, which are enclosed farmsteads usually dating from roughly the sixth to the tenth century, were frequently furnished with souterrains, and the two features are commonly found together across Ireland. Where a souterrain once existed here, its roof, likely constructed from large stone lintels, has given way, leaving the characteristic depression that field surveyors learn to recognise. The association with the adjacent ringfort lends the hollow credibility as a genuine archaeological remnant rather than a natural hollow or drainage feature, though no excavation appears to have confirmed its origins.