These structures are found across Ireland in their hundreds, and their precise purpose has long been debated. Current thinking holds that they served as places of refuge, cool storage for perishables, or both, typically constructed in association with a nearby settlement or ringfort. The Ballyculloo example is recorded as a monument, which means it has been formally identified and catalogued, though very little about its specific dimensions, condition, or construction details is presently available in the public domain.

Souterrains were generally built by digging a trench, lining it with drystone walling, roofing it with large lintels, and then covering the whole structure back over with earth. The result is a passage that is nearly invisible from above, which is partly why so many survive at all and partly why they were so effective for their original purposes. They are most common in areas of early Christian settlement, and their distribution across Connacht, including County Galway, reflects the density of that period's activity in the west of Ireland. Without specific excavation records or field notes for the Ballyculloo site, it is difficult to say more about when it was built, who built it, or what relationship it might have had with surrounding features in the landscape.