The bank that defines it is overgrown and worn, yet it traces a clear oval roughly 45 metres across at its widest, with an outer fosse, a defensive ditch, running around the south-west to north-north-east arc. What catches the eye, once you know to look, is the unevenness: the south-western section is noticeably more substantial than the rest, rising to an external height of about two metres and widening to seven metres, suggesting that this was either the most carefully constructed portion or simply the best protected from later disturbance.

Enclosures of this kind belong to a broad class of earthwork found across Ireland, related to the rath or ringfort, a type of enclosed farmstead that was in common use from the early medieval period onwards. A rath typically consists of a circular or oval area surrounded by one or more earthen banks and ditches, and would once have contained a dwelling, outbuildings, and perhaps a small yard. Whether this particular enclosure at Lissian served a domestic, agricultural, or some other purpose is not recorded, but its form, with two opposing entrances at the east and west ends, each about two metres wide and both now modernised, implies it has remained in practical use at some level through to relatively recent times. A closely related rath survives approximately 220 metres to the west along the same ridge, which suggests the area once supported more than one enclosed settlement, perhaps functioning in some proximity to one another.