The circle measures nine metres across, which is modest even by the standards of ancient field enclosures, and the people who constructed it went to some trouble to make the interior level on sloping ground, cutting into the upslope on the south-east side and raising the platform on the north-west, leaving a floor that sits roughly level despite the hillside falling away beneath it.

Drystone enclosures of this kind, built without mortar from whatever stone lay to hand, appear throughout the Irish uplands and are notoriously difficult to date without excavation. Their functions varied: some served as small stock enclosures, others as the foundations or boundaries of seasonal settlement. What makes the Derreenacrinnig site particularly legible as a place of past habitation is its relationship to the surrounding landscape. Two hut sites, the low platforms or footings of former dwellings, lie close by, one roughly twenty-five metres to the north-north-east and another approximately thirty-five metres to the south. Together, the three features suggest a small cluster of activity on this hillslope, overlooking the valley towards Mullaghmesha, though whether they were all in use at the same time remains unknown without further investigation.

The enclosure sits among occasional surface boulders in an area still used for rough grazing, which means the remains are in the kind of quiet, undisturbed state that makes such sites easy to walk past without recognising what they are. The collapsed wall, recorded at just over half a metre in height and roughly seventy centimetres thick, retains enough form to trace the circuit of the original structure, though its covering of vegetation means close attention is needed to follow it around the full nine-metre diameter.