Roughly sixty metres across, it is defined by a discontinuous bank of earth and stone, revetted on its outer face with small boulders, and accompanied by a fosse, the term for a defensive or boundary ditch, running along its north-western and northern sides. That fosse is about three metres wide and just over half a metre deep, modest by any measure, though at the south-western arc it widens and merges into a scarp faced irregularly with stones and boulders, suggesting the builders made practical use of the natural break in the ground. There is no identifiable entrance, and nothing survives inside.

What makes the site quietly puzzling is how little it gives away. Circular enclosures of this kind appear throughout Ireland and can belong to a wide range of periods and functions, from early medieval ringforts used as farmsteads to prehistoric ceremonial sites, but without excavation the Kilbeg example offers no clear answers. What can be said is that it was already visible and map-worthy by 1838, when the Ordnance Survey recorded it on their six-inch map as a small mound enclosed by a bank. That early cartographic attention at least confirms the earthwork's presence before any modern disturbance, though it also underlines how long this feature has sat in the landscape without much further explanation being sought.