What looks like a modest ringfort, a roughly circular drystone enclosure used in early medieval Ireland as a farmstead or place of refuge, may actually sit on the footprint of something older. A spread of loose stone around the base of the enclosing wall, between three and three and a half metres wide on the outside, suggests the present structure was built along the line of an earlier cashel wall. A cashel is a type of stone-walled enclosure, the western Irish equivalent of an earthen ringfort, and when one is reused or built over, the evidence tends to survive in exactly this way: a rubble skirt at the base, flush with the interior on one side but offering no visible facing on the other.

The enclosure at Lissylisheen is subcircular, measuring roughly nineteen metres north to south and sixteen metres east to west, with a drystone wall about a metre thick. The interior height of the wall varies between thirty centimetres and eighty centimetres, while externally it stands between one point one and one point five metres. A second drystone wall, just over seven metres long, is visible within the south-west quadrant of the interior, though its precise function is unclear. The site sits within a large field system and is surrounded by rock outcrop and thin grass cover, with a roughly east-west ravine about fifty metres to the south. It was already noted on the 1920 edition of the Ordnance Survey six-inch map. Approximately fifteen metres to the north-north-west lies a wedge tomb, a type of megalithic burial monument dating to the late Neolithic or early Bronze Age, making this a landscape with human activity reaching back several thousand years.