This ringfort in Greenane, known locally as 'the lios', the Irish word for a fairy fort or enclosure, carries the usual marks of its type: a roughly circular platform around thirty metres across, defined by a scarp rising between one and one and a half metres, worn down over centuries by weather, livestock, and the creep of neighbouring field boundaries. What sets it apart, at least in local memory, is what lies beneath it. A souterrain, a man-made underground passage or chamber typically built during the early medieval period for storage or refuge, is said to exist within the rath. It has long since been closed up, its entrance lost or deliberately blocked, leaving only the knowledge of its existence behind.

Ringforts of this kind were built across Ireland during the early medieval period, roughly between the fifth and twelfth centuries, and served as enclosed farmsteads for individual families or small farming communities. The earthen bank or scarp that defines the Greenane example would originally have been topped with a timber palisade or dense hedging, making the interior a defensible domestic space. This particular fort sits on a level break in a south-facing slope, a practical choice that would have offered shelter from northerly winds while giving those inside a clear view southward over Bantry Bay and the Sheep's Head Peninsula. A stream and a field boundary now cut across the western arc of the enclosure, interrupting what was once a continuous ring. The western portion, in other words, is gone, absorbed into the working landscape around it.