It is a souterrain, a type of structure built during the early medieval period in Ireland, typically by hand-digging a trench, lining it with drystone walling, and roofing it with heavy capstones before covering it over with earth. These passages are found across the country in their hundreds, most often associated with nearby settlement sites, and their purposes likely ranged from food storage, exploiting the cool and stable underground temperature, to refuge in times of danger. The Tinnahally example is one of many Kerry souterrains that have been noted and catalogued but whose details remain, for now, largely out of reach for the general reader.

The specific history of this souterrain, including when it was constructed, by whom, and in what condition it survives, is not currently available through public records. Kerry has a particularly dense concentration of early medieval activity, and souterrains in the county are frequently linked to ringfort settlements, the circular enclosed farmsteads that dot the landscape and date broadly from the sixth to the twelfth centuries. Whether the Tinnahally souterrain connects to such a settlement nearby is a question the available material cannot yet answer. It remains one of those quiet gaps in the record, a known unknown, present enough to be counted, but not yet fully described.