That absence is, in its own way, the point. What once stood here, a circular embanked enclosure of somewhere between fifteen and twenty metres across, was recorded on the Ordnance Survey six-inch map of 1838 with enough detail to suggest a substantial feature in the landscape. By the time the same area was surveyed again in 1917, it had already shrunk in the cartographic record to a smaller hachured circle of perhaps ten to fifteen metres. Today, land reclamation has finished the job, and the ground gives nothing away.

A barrow is a burial mound, typically prehistoric in origin, sometimes consisting of little more than a low earthen heap, sometimes ringed by a bank and ditch. The Larganboy example, whatever its precise form, was sited in a manner consistent with such monuments: on elevated ground at the edge of a slope, positioned to be visible across the surrounding terrain or, depending on one's interpretation, to mark a boundary between the living world and whatever lay beyond the ridge. The location was not random. Two comparable mound barrows survive in the same townland, one roughly 600 metres to the south-east and another about 700 metres to the north-west, suggesting that this vanished feature may once have formed part of a loose cluster of funerary monuments across the landscape. Whether all three were contemporary is unknown, but their shared townland and their spacing along the same ridge line gives the arrangement a certain quiet coherence.

The destroyed barrow at Larganboy is a reminder that the archaeological map of Ireland is full of monuments known only through their cartographic ghosts, shapes recorded by nineteenth-century surveyors that have since been levelled by drainage works, ploughing, or field improvement. The 1838 map caught this one just in time, though not in time enough to save it.