What makes it unusual is not just its scale but its peculiar boundary: on the north-eastern side, there is no wall at all. Instead, a straight natural rock outcrop, running for some 80 metres, does the work of masonry, folded into the enclosure's design as though its builders saw no reason to duplicate what the landscape already provided.

The enclosure was identified by John Cronin and Associates during pre-development survey work prior to wind farm construction in the Barnastooka townland. The rubble wall that defines the remaining sides varies considerably in condition. On the western and southern stretches it survives to around 0.6 metres high and 0.6 metres wide, with stone slabs laid horizontally one on top of another in what is described as a domino arrangement. Elsewhere it has collapsed to little more than a loose line of stones, and along the eastern side it has been partly or entirely swallowed by peat growth. The enclosure is interpreted as a settlement enclosure, a type of boundary that gathered domestic and agricultural life into a single defined space. Five hut sites and a small livestock pen were identified inside it, each sitting against the inner face of the wall. On the western side, a corral-like entrance gap suggests that animals were regularly moved in and out, and a further relict wall extends westward from that point. The phrase "under better climatic conditions" in the site's interpretation is worth pausing on: it hints that this ground, now waterlogged and moss-covered in places, may once have been workable arable land before the bog advanced. The whole complex sits approximately 150 metres north-west of a wedge tomb, a megalithic monument type associated with the later Neolithic and earlier Bronze Age, suggesting that human activity in this upland was layered across a long span of time. A possible small cairn, measuring 2.5 by 1.75 metres, was also noted on a slope just south of the enclosure's south-western edge.