What survives at Ardkill is only half an enclosure, and even that half is easy to miss. Set in level, rushy pasture roughly 150 metres south-east of a medieval church and its associated graveyard, the earthwork now presents itself as a D-shape, the flat side of the D formed not by any ancient boundary but by a modern field bank that has quietly replaced whatever once stood there. The original monument was almost certainly circular or oval, a form of enclosure common across early medieval Ireland, typically used to define a farmstead, a religious precinct, or a place of assembly. Only the western half remains as a readable earthwork.

What is left measures around 26 metres across its north-east to south-west axis, and the surviving bank runs from south to north-west, low and grass-covered, about five metres wide and just under half a metre high. It is, in other words, a slight feature in a wet field, the kind of thing that asks you to look carefully rather than announcing itself. The eastern half of the original enclosure has left no visible trace at ground level, absorbed into the surrounding pasture. The proximity to the medieval church suggests the two features may have had some relationship, whether that means the enclosure predates the church and the ecclesiastical site grew up beside it, or something else entirely, the surviving evidence does not say.