A field in County Galway holds the ghost of a subcircular enclosure, a feature so thoroughly erased from the landscape that by the time anyone looked carefully at it, even the question of what it once was could not be answered with confidence.

The 1838 edition of the Ordnance Survey six-inch map records it clearly enough: an embanked enclosure of roughly oval form, planted around with a ring of trees, the kind of deliberate planting that might suggest either a working ringfort adapted into a later landscape feature, or something always intended as ornamental. A ringfort, to clarify the term, is a roughly circular earthen or stone enclosure used in early medieval Ireland as a farmstead, typically defined by a bank and ditch. By the time of the 1946 to 1947 aerial revision, the trees were gone and a field boundary had been pushed across the interior from west-southwest to east, cutting through whatever remained of the original form. The enclosure measured approximately 55 metres northwest to southeast and 40 metres northeast to southwest, dimensions consistent with a modest ringfort, though that identification was never settled. When an inspector examined the site in 1961, the monument was already so poorly preserved that a clear classification was impossible. It has since been levelled entirely. Apart from a slight rise in the field surface to the north of the field boundary, no trace survives above ground.

What the Ballydonagh enclosure leaves behind is not archaeology so much as a problem in interpretation, a site that slipped past the point of legibility before anyone could pin down its origins, and has now passed beyond recovery altogether.