It exists more convincingly on paper than it does in the ground, or at least on the surface of it.

The site first appears on the 1911 edition of the Ordnance Survey six-inch map, depicted as a subcircular enclosure, meaning a roughly circular or oval boundary feature, the kind of form associated in Ireland with early settlement, farming, or ritual use across many centuries. What is notable is its absence from the earlier 1837 edition of the same map series, suggesting it was either unrecorded by the original surveyors or had not yet been exposed at that time. When fieldworkers returned to locate it in person, they could not. The most plausible explanation is straightforward and quietly unsettling: the dunes moved. Sand dune systems along the Atlantic coast are not static landscapes. They migrate, accumulate, and bury, sometimes slowly and sometimes with surprising speed, swallowing field boundaries, walls, and earthworks with little ceremony. The enclosure at Mullaghmore appears to be one such casualty, visible to surveyors in 1911 and gone, or at least deeply buried, sometime after.