At Garrane in County Cork, tucked into the south-eastern quadrant of a ringfort, that is precisely what survives: a souterrain, an underground passage or chamber constructed from dry-stone walling and roofed with flat flagstones, of the kind commonly built during the early medieval period in Ireland. These structures served various purposes, from storage to refuge, and are frequently found within the enclosures of ringforts.

This particular souterrain extends roughly 16.8 metres south-west from the ringfort's entrance, disappearing under the bank. It is not alone. Writing in 1934, a researcher named Bowman noted the presence of two souterrains within the fort, both of them stone-lined and covered with flagstones. The second lies in the northern half of the interior. The pairing is notable; two souterrains within a single enclosure suggests either a settlement of some complexity or a community with particular needs for underground space, whether for cool storage of dairy produce, for sheltering valuables, or for retreat in times of danger. The ringfort itself, the earthen enclosure within which these passages sit, is a type of enclosed farmstead that was widespread across Ireland from roughly the fifth to the twelfth centuries.