This one in Ballygrennan, County Limerick, does the opposite: it has vanished almost entirely, surviving now only as a reference number in the national monuments record and a faint circle on a nineteenth-century map. What was once a rath, the Irish term for a ringfort, a type of enclosed farmstead typically dating from the early medieval period and defined by a circular earthen bank and ditch, has been levelled so completely that no surface trace remains visible even on modern satellite imagery.

The evidence for its existence comes from the first-edition Ordnance Survey six-inch map, published in 1840, which records a circular enclosure roughly 22 metres in diameter, enclosed by a bank, sitting in what is now reclaimed pasture just south of a watercourse that marks the townland boundary with Baunnageeragh. By the time the 25-inch Ordnance Survey revision was completed in 1897, the feature had disappeared from the record entirely, meaning the monument was levelled somewhere in the intervening decades, most likely as agricultural improvement continued to reshape the Irish countryside in the latter half of the nineteenth century. A possible second ringfort is recorded immediately to the east, catalogued under the reference LI040-090, suggesting this was once a landscape with at least two such enclosures in close proximity, a pairing not unusual in areas of early medieval settlement. The site was compiled for the monument record by Martin Fitzpatrick, with details uploaded in June 2021.

For anyone curious enough to visit, the location sits in ordinary working farmland and there is genuinely nothing to see at ground level. The interest lies entirely in the exercise of reading the landscape against the 1840 map, available through the OSi historical map viewer, and recognising that the flat, unremarkable pasture once held a structure that would have been a familiar and functional part of early medieval rural life. The nearby watercourse and townland boundary are the only fixed reference points remaining.