Roughly circular in plan and approximately thirty metres in diameter, its defining feature is not what can be seen but what may lie beneath: the existing stone wall is thought to possibly sit on earlier foundations, suggesting that whatever function this place once served, the site itself may have been in use across more than one period of occupation.

The enclosure belongs to a broader class of field monuments common across early medieval Ireland, where subcircular stone-walled enclosures, sometimes called cashels, were used to define farmsteads, religious sites, or places of communal activity. A cashel is, in essence, a roughly circular enclosure bounded by a dry-stone wall, distinct from an earthen ringfort. What makes the Lislarheenmore site particularly interesting is its proximity to another such structure: a cashel sits just thirty metres to the north-west, meaning the two monuments occupy the same hillside in close company. Whether they were contemporary, successive, or served entirely different purposes is not recorded, and that ambiguity gives the landscape an quietly unresolved quality. The valley below, drained by the Caher River, would have been a navigable and productive corridor in early historic times, and elevated positions overlooking river heads were frequently chosen for enclosures precisely because they commanded a view over the approaches.