Measuring roughly 31 metres across, it is enclosed by an earthen bank so low and so worn that it barely registers as anything deliberate. The western arc survives best, though even there a disused quarry has crowded in against it, as if the landscape has been quietly cannibalising itself for centuries.

Circular earthwork enclosures of this kind are among the most common archaeological features in the Irish countryside, and among the least understood. They are generally interpreted as enclosed farmsteads or settlement sites, most likely dating from the early medieval period, roughly the fifth to the twelfth centuries, when such ringworks formed the basic unit of rural life across Ireland. The earthen bank, a berm of piled soil rather than a mortared wall, would originally have been considerably more imposing. At Lismaline, whatever height it once had is long gone. Complicating the picture further, the north-eastern sector of the enclosure has been cut across by the wall-footings of an old field fence running on a north-west to south-east axis, a later agricultural intrusion that pays no attention at all to what lies beneath it.