That absence is itself remarkable. The OS mapping programme, which swept across Ireland in meticulous detail from the 1830s onwards, recorded field boundaries, ruined walls, and the faintest traces of antiquity, yet this small monument slipped through entirely, surviving in the landscape without ever acquiring a cartographic existence.

The feature is a ditch barrow, a type of prehistoric funerary monument defined not by a raised mound but by a surrounding circular ditch, roughly fifteen metres across on its north-northwest to south-southeast axis. It sits on waterlogged ground within Sonna Demesne, with a separate enclosure about thirty metres to the north-northwest. What makes its current condition particularly layered is that a later ditch, constructed after 1700, cuts straight across it, bisecting the ancient form with a line of purely agricultural practicality. The monument was identified not through excavation or ground survey but through aerial photography, the kind of large-scale digital imagery that has quietly revolutionised how archaeologists locate sites that offer little surface drama to the passing eye. Boggy, low-lying ground tends to preserve earthworks well even as it discourages close investigation, which may explain why something this size remained unrecorded for so long.