These subterranean structures, found throughout Ireland but particularly common in counties like Cork, Kerry, and Donegal, were typically built between the 6th and 12th centuries AD. Whilst their exact purpose remains debated amongst archaeologists, they likely served multiple functions; secure storage for food and valuables, temporary refuge during raids, or perhaps holding ritual significance for the communities that constructed them.

The Ballyliffin souterrain follows the typical design of these structures, consisting of stone-lined passages and chambers carved into the earth or built using drystone walling techniques. Many souterrains were associated with ringforts or other early medieval settlements, suggesting they were integral to daily life rather than isolated features. The passages were often deliberately narrow and low, forcing anyone entering to crouch or crawl, which would have made them easier to defend if used as hiding places during times of conflict.