This is a rath, the most common type of ringfort found across Ireland, built during the early medieval period as an enclosed farmstead for a single family or small community. What gives this one a particular character is the combination of its defences: a bank standing 1.65 metres high, an outer fosse, or ditch, running around the southern and south-western arc to a depth of 1.6 metres, and a second, shallower fosse to the north that tends to hold water. That waterlogged northern ditch is a small but telling detail, suggesting the natural lie of the land was worked into the design rather than simply overcome.

The enclosure measures roughly 36.5 metres north to south and 33 metres east to west, placing it comfortably within the typical range for a rath of this kind. A gap of about two metres in the bank to the north-north-west marks what was almost certainly the original entrance. Perhaps the most intriguing feature lies beneath the surface: a possible souterrain has been identified in the interior. Souterrains are stone-lined underground passages or chambers, built during the early medieval period and thought to have served as refuges, cool storage spaces, or both. Their presence in a ringfort often suggests a site of some domestic complexity, where a family had both the resources and the reason to invest in subterranean construction. Whether the Lisheen example has ever been fully investigated is not recorded, and its precise form remains uncertain.