Scattered across the Irish midlands are thousands of ringforts, the enclosed farmsteads of early medieval Ireland, most of them reduced by now to little more than a smudge in the grass. The one at Ballynakill in County Kildare is a particularly quiet example of the type: a circular enclosure roughly 38 metres across, its defining earthen bank worn down to just a few centimetres above the surrounding pasture, its outer fosse, the shallow ditch that would once have added both drainage and a degree of defence, barely registering at 10 to 30 centimetres in depth. What survives sits on the western leading-edge of a broad terrace along a moderately steep ridge, a position that would have given its original occupants a useful outlook over the land below.

The enclosure is not in good condition. A modern field bank cuts across its northern side, and a large rectangular depression, 14 metres long, 5 metres wide, and 2 metres deep, has been cut into the northwestern arc of the bank, obscuring that portion of the original circuit entirely. The site was identified from aerial photography by Holton in 1985, which is often how such low-profile monuments come to wider attention; what the eye misses at ground level, oblique light from above can reveal as a pattern of crop marks or shadow. When road construction on the Kinnegad to Enfield to Kilcock bypass brought archaeological testing to within 50 metres of the monument, no archaeological deposits were found in that area, leaving the internal story of the Ballynakill rath, who farmed it, when it was built, and how long it was occupied, entirely unresolved.