The earthen bank that once enclosed a near-perfect circle of ground on this north-facing slope in County Cork has been worn down, ploughed back, and largely lost. Yet the arc that remains, running from south-south-east to west-north-west, is enough to read the original shape: a ringfort, the type of enclosed farmstead that served as the basic unit of rural settlement in early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries. Thousands were built across the country; a great many have since vanished into the fields that surround them.

This one appears on the Ordnance Survey six-inch map of 1842, rendered as a hachured circular enclosure, the standard cartographic shorthand for an earthwork of this kind. By the time the 1904 and 1937 OS maps were made, only the arc of the bank was still legible on the ground. What survives today measures approximately 30.5 metres east to west and 30 metres north to south, with the earthen bank standing roughly 0.75 metres above the interior and 1.6 metres above the outer ground level. A fosse, the external ditch that would once have reinforced the enclosure, now reads only as a gentle slope down to the base of the bank. The interior is level. In 1934, a researcher named Bowman recorded this site as one of five ringforts, all levelled or partially levelled, that stood on land belonging to a Mr Leader in the same townland area. The grouping is a reminder that these enclosures were rarely isolated; families and communities built and farmed in clusters, and the landscape around Knockastuckane would once have held considerably more of them than it does today.