The enclosure measures roughly 70 metres east to west and 36 metres north to south, defined by a collapsed drystone wall between two and three metres thick along its surviving arc from the south-west, around the north, and back to the south-east. Elsewhere the wall has vanished entirely, leaving a partial bracket rather than a closed ring. Inside, the space is divided by internal walls, with a curving wall sitting east of centre adding a further layer of subdivision that seems too deliberate to be incidental.

What makes the site particularly difficult to read is its clustering of features. A rectilinear annexe, roughly 19 metres by 5 metres, presses against the south-eastern edge, with further low walls radiating outward to the west-north-west and north. A number of associated house remains lie nearby, and a corngrowing burial ground, a CBG, sits just nine metres to the east. A corngrowing burial ground, sometimes called a cillín, is a small unconsecrated plot historically used to inter unbaptised infants or others excluded from formal church burial, and their presence near a settlement is not unusual in post-medieval Ireland. The enclosure itself is tentatively dated to the post-medieval period, though the collapsed and fragmentary state of the walls makes any precise dating difficult.

Knockmaa itself carries a long folkloric association with Fionnbarra, king of the Connacht fairies in Irish tradition, which gives the surrounding landscape a certain accumulated resonance. The enclosure at its base is quieter and more ambiguous, a scatter of tumbled stone that raises more questions about how people organised their living and burial spaces here than it comfortably answers.