An esker is a long, sinuous ridge of gravel and sand deposited by meltwater streams running beneath a glacier, and in the Irish midlands these ridges were often chosen as routes, boundaries, or focal points precisely because they stood above the surrounding boggy lowland. This one, oriented roughly north-northeast to south-southwest, carries a scrub-covered earthwork only about ten metres across. What makes it quietly odd is the absence of any visible fosse, the external ditch that typically accompanies an enclosing bank, and the complete absence of any identifiable entrance. Something was enclosed here, but how people got in or out has left no obvious trace.

The enclosure was recorded only on the 1915 edition of the Ordnance Survey six-inch map, suggesting it had either escaped earlier notice or had been sufficiently degraded by then to resist confident classification. The bank itself is composed of earth and stone, and survives unevenly; it stands higher and wider on its western side, where it reaches nearly a metre in external height and three and a half metres in width, than on the eastern side, where it is considerably reduced. Inner and outer facing stones are still visible along the north-northwest to east-northeast arc, indicating that the original wall construction had a width of between 1.3 and 1.7 metres, consistent with a deliberately built rather than merely piled structure. Running across the interior, and bisecting the enclosure, is an intermittently visible line of limestone boulders on a northeast to southwest alignment. Whether this feature is contemporary with the enclosure, earlier, or a later intrusion is not clear from what survives.