That juxtaposition alone makes it worth knowing about: a structure likely over a thousand years old, once standing in open pastureland, now surrounded by footpaths and parked cars.

The site is a rath, the most common type of Irish ringfort, typically consisting of a circular or subcircular area enclosed by one or more earthen banks and ditches, and used during the early medieval period as a farmstead or high-status residence. This particular example is subcircular in plan, measuring roughly 51.5 metres on its northwest to southeast axis. It is defined by two earthen banks with an intervening fosse, the fosse being the ditch between the banks, and survives in fair condition on its southeastern to northwestern arc. The northeastern section has fared less well; no visible trace remains of the fosse or outer bank on that side, likely eroded or disturbed over the centuries. A field bank radiates outward from the ringfort at the west-northwest, hinting at the agricultural organisation of the surrounding land in earlier periods. Perhaps most intriguing is the souterrain in the interior. Souterrains are underground stone-lined passages or chambers, constructed during the early medieval period and associated with storage, refuge, or possibly ritual use. Their presence within a rath often signals a site of some complexity and suggests the enclosure was more than a simple farmyard boundary.

The site is not signposted or presented as a visitor attraction, and finding it means navigating the residential streets of Mervue. The earthworks are most legible from the southeastern approach, where the double-bank-and-fosse arrangement is best preserved and easiest to read as a coherent structure. The souterrain is not accessible, but the raised interior platform and surviving banks give a clear enough sense of the original form.