This one, sitting in wet pasture in Mitchelstowndown East, County Limerick, was only confirmed to exist by looking down from above. It belongs to a cluster of three barrows, and its presence was not recorded on the Ordnance Survey Ireland six-inch maps, meaning it sat unregistered in the official cartographic record for generations, visible to no one walking past and unknown to anyone consulting a map.

A barrow is, in its simplest form, a burial mound, typically prehistoric in origin, often enclosed by a surrounding ditch. A ditch-barrow is defined by that encircling depression rather than by any significant upstanding mound, which is partly why these features can be so easy to miss at ground level. The site came to light during aerial survey work carried out for the Bórd Gáis Éireann Curraleigh West to Limerick gas pipeline in November 1984, when photographs taken at a scale of 1:5000 caught a circular cropmark on the ground below. Cropmarks form when buried features, such as ditches or disturbed soil, affect the growth of vegetation above them, creating patterns that are invisible from the ground but legible from the air. In this case the cropmark had a diameter of approximately 4.5 metres. The feature was later confirmed as a faint trace on Ordnance Survey orthophotographs taken between 2005 and 2012, and was clearly visible on a Google Earth image dated 20 March 2018. The record was compiled by Fiona Rooney and uploaded to the national monuments database in September 2021.

Because the feature is identified primarily through aerial and remote sensing evidence rather than ground investigation or excavation, there is little to observe with the naked eye on a visit. The surrounding land is wet pasture, and the barrow sits within a group that includes a possible ditch-barrow immediately to the west. Anyone interested in seeing the cropmark evidence would do better to start with the Google Earth orthoimage or the pipeline survey photographs than to expect a visible earthwork in the field. The real interest here lies less in what the eye can see than in what the process of discovery reveals: that the Irish landscape continues to give up features that eluded earlier surveyors, found not by digging but by the patient study of shadows and grass.