What remains is barely legible at ground level: a shallow fosse, a ditch that once defined the outer edge of the enclosure, tracing a near-perfect circle roughly 28 metres across. The earthwork itself is gone, but the ghost of it persists, visible in aerial photographs as a cropmark, where the buried outline of the old bank causes crops or grass above it to grow at a slightly different rate, revealing the form of the fort to a camera where a walker on the ground would notice almost nothing.

Ringforts, known in Irish as raths, were the most common form of enclosed farmstead in early medieval Ireland, typically dating from roughly the sixth to the twelfth century. They consisted of a raised circular bank, sometimes topped with a timber palisade, surrounding a family's dwelling and ancillary buildings. The one at Knockardbane appeared on Ordnance Survey six-inch maps from as early as 1842, marked clearly as a hachured circular enclosure with a diameter of around 25 metres. It was still recorded on the 1905 edition, and again on the 1937 revision, by which point it was noted as a raised circular area rather than a sharply defined bank, suggesting the earthwork was already softening with age and agricultural pressure. It endured long enough to be mapped three times across nearly a century of surveying, then disappeared within a generation.