In a field of pasture at Knocklong West in County Limerick, the Cork to Dublin line cuts directly through what was once a circular earthwork, slicing the monument in two and leaving each half to its own slow fate. One half has disappeared almost entirely into the ground; the other survives, just barely, as a ghostly curve visible only from the air.

The earthwork was recorded on the Ordnance Survey Ireland six-inch map of 1840 as a circular platform defined by a wide foss, which is simply a ditch or trench cut around an earthen enclosure, a common feature of early medieval and prehistoric sites across Ireland. By the time the twenty-five-inch edition was surveyed in 1897, the monument had already been bisected by the railway and the record describes an oval-shaped platform measuring roughly forty metres northwest to southeast and twenty-seven metres northeast to southwest, cut through along its northeast to southwest axis by the line. Between 2011 and 2013, Digital Globe satellite imagery captured a D-shaped cropmark to the south of the tracks, approximately thirty metres by nine metres, tracing the buried outline of the southern half. Cropmarks form when buried features affect how vegetation grows above them, leaving faint colour differences in grass or tillage that become visible from above in dry conditions. No surface trace of the northern half remained by the time of survey.

There is nothing to see at ground level, which is part of what makes this site quietly interesting. The field is in agricultural use and the northern portion of the earthwork has left no visible impression. The southern section, however, continues to reveal itself to aerial and satellite observation, with a curving cropmark still legible on Google Earth imagery. For anyone interested in the site, the most productive approach is through online mapping tools rather than a site visit, comparing the 1840 six-inch OSi map, which shows the monument intact, against the 1897 edition and then the satellite imagery, watching the earthwork shrink across each layer of record until only a faint arc in the grass remains.