This one in Mitchelstowndown West, County Limerick, does none of that. It exists, as far as anyone can currently tell, only in a single frame of aerial photography taken on the 3rd of November 1984, visible as a circular feature in reclaimed pasture roughly 225 metres north of the Morningstar River. By the time satellite imagery was consulted, sometime between 2011 and 2013, nothing remained on the surface. It does not appear on Ordnance Survey Ireland historic maps at all. What you have, in other words, is an earthwork that is known primarily through its own disappearance.

The circular feature was identified during aerial survey work commissioned for the Bórd Gáis Éireann Curraleigh West to Limerick gas pipeline, photographed at a scale of 1:5000 under reference BGE 2576. Pipeline surveys of this kind, carried out from the air before ground works begin, have been responsible for identifying a considerable number of previously unrecorded sites across Ireland, where crop marks or soil discolouration can betray buried features that leave no impression on the modern landscape. In this case, the feature sits in what is now reclaimed agricultural pasture, and the Morningstar River running to its south forms the townland boundary between Mitchelstowndown West and Glenlary. A possible barrow, a type of prehistoric burial mound, lies approximately 120 metres to the northwest, recorded separately under its own reference. Whether the two features are related in any meaningful way is not currently known. The site was compiled by Martin Fitzpatrick and uploaded to the record in September 2021.

There is, practically speaking, nothing to see on the ground. The surrounding farmland is private, and the site carries no marker, no signage, and no visible surface trace. Its interest lies less in what a visitor might observe than in what the record itself represents: the routine work of cataloguing features that agriculture, drainage, and time have already erased. For those interested in the broader archaeology of the Limerick countryside, the nearby possible barrow offers a companion entry in the national monuments record, and the Morningstar River valley rewards attention as a boundary landscape with its own quiet layering of land use across centuries.