The earthwork in question is a rath, the Irish term for a ringfort, which was the most common form of rural settlement in early medieval Ireland. These were not military fortifications in any grand sense, but farmsteads, enclosed by one or more circular banks of earth to protect livestock and family from the ordinary hazards of the countryside. The one at Inchycullane sits quietly in grazing land, its roughly forty-metre diameter still traceable as a continuous circuit of bank, ditch, and outer bank, at least where the vegetation has not swallowed it whole.

The structure follows the classic pattern of a multivallate rath, meaning it has more than one enclosing element. An earthen inner bank, a fosse (a drainage or defensive ditch cut into the ground), and an outer bank are all present along the western to north-eastern arc, giving a clear sense of the original engineering even where the dimensions are modest. On the eastern side, however, the bank and fosse appear to have been levelled or removed at some point, leaving a gap in the sequence. A possible cattle gap survives at the south, which would have served as a practical entrance for animals moving in and out of the enclosure. Inside, a raised area protrudes from the inner face of the bank at the south-west, its function uncertain but perhaps the platform of a vanished structure. The site was noted in the 1840s in the Ordnance Survey Name Books for the parish of Kilcummin, which places it at the northern end of the Inchycullane townland, suggesting it was a recognised landmark even then, long after its original use had ended.

The interior is now heavily overgrown, with the south-eastern quadrant described as completely inaccessible due to dense vegetation. This is a common fate for earthworks in active farmland, where the bank itself is left undisturbed but the enclosed ground fills gradually with scrub and bramble. The visible portions of the bank and outer earthworks remain the most legible part of the site, particularly along the north to north-east, where the outer bank still reaches a height of about one metre above the surrounding ground.