At Rathurd in County Limerick, a semi-circular enclosure sits on the north-west-facing slope of a small hillock in undulating pasture, so thoroughly flattened by time that its bank rises only a few centimetres above the surrounding ground. The internal height of that bank measures roughly 0.1 metres, the external face a little more at 0.2 metres, and the whole thing spans approximately 54 metres north to south. It is the kind of earthwork that a casual walker might cross without a second glance.

Enclosures of this type are generally understood to be the remains of early medieval ringforts, circular or near-circular enclosed settlements that were once the basic unit of rural life across Ireland, typically defined by one or more earthen banks and ditches and used to protect a farmstead and its livestock. This particular example sits around 80 metres north-north-west of Rathurd Castle, and it is almost certainly the feature noted in the Ordnance Survey Letters, which record that there was once "an old fort now nearly level with the ground about 30 yards NW of" that castle. Those letters, compiled as part of the nineteenth-century Ordnance Survey of Ireland, frequently captured local knowledge about earthworks that were already fading from view, and this entry is a small example of that documentary habit preserving something the ground itself can no longer clearly state. The record as it stands was compiled by Denis Power and uploaded in June 2013.

The site lies in pasture, and the surviving bank, at 2.6 metres wide, is subtle enough that knowing roughly where to look is more or less essential. Views to the east, west, and north are noted as good, which gives some sense of why a hillock position would have been chosen in the first place, whether for observation, for status, or simply because elevated, well-drained ground suited a farmstead. Rathurd Castle itself provides the most useful landmark for orientation, and the enclosure sits to its north-north-west. There is no formal access infrastructure here; this is agricultural land, and the remains are, by any honest description, extremely slight.