On the southern slopes of Annagh Hill in County Limerick, a ringfort, or rath, an enclosed circular or oval farmstead typically dating from the early medieval period, has been reduced to precisely that: a gentle arc absorbed into the edge of a modern pasture field, legible only if you know what you are looking for.

The monument was recorded as an oval-shaped enclosure of approximately 28 metres in diameter on the 1840 edition of the Ordnance Survey six-inch map, suggesting it was still largely intact at that point. By the time the 25-inch OS map was produced in 1897, the picture had changed considerably. The site was shown as a semi-circular earthwork rather than a complete enclosure, with a curving field boundary running along its western side. The implication is clear: sometime in the second half of the nineteenth century, the western portion of the original enclosing bank was levelled, most likely to improve or regularise agricultural land. Rather than disappearing entirely, that bank was folded into the existing field boundary, where it has remained ever since. The site has been documented by Edmond O'Donovan drawing on cartographic comparison and aerial photography, including Google Earth orthophotos taken in June 2018, which show the curving western field boundary still tracing the original form of the rath.

Because the site sits on pasture and has not been formally excavated or surveyed on the ground, there is no publicly available access and no visitor infrastructure of any kind. What the record offers instead is a lesson in how to read a landscape from a distance. The curved field boundary visible on aerial imagery is the key feature, a line that follows an arc no practical agricultural logic would produce, and which only makes sense when you know there was once a circular earthwork here. For anyone interested in this class of monument, the comparison between the 1840 and 1897 OS maps, both freely available through the OSi historical map viewer, shows the incremental erasure in a way that is genuinely instructive about how so many Irish ringforts have vanished since the nineteenth century.