That is, in a sense, the point. On a gentle rise in north County Galway, a roughly square enclosure of around twenty-five metres by twenty-five metres once marked the ground. It has left no trace that a person standing on the land today could detect. The only reason we know it existed at all is that an aircraft flew over in the summer of 1965 and the light was right.

Aerial reconnaissance conducted in July 1965, catalogued under the reference CUCAP ALR 82, caught the faint cropmark signature of a rectilinear enclosure sitting on slightly elevated ground, approximately a hundred metres north-northeast of a separate, already-recorded enclosure nearby. Cropmarks form when buried features, whether ditches, banks, or walls, affect the moisture available to growing crops or grass above them, producing subtle variations in colour and height that are invisible at ground level but can be read clearly from the air under the right conditions. The 1965 overflight preserved just enough of that pattern to allow the site to be recorded. No visible surface trace survives now, which means the enclosure exists entirely as a coordinate, a photograph, and a few lines of description in the Archaeological Inventory of County Galway, compiled by Olive Alcock, Kathy de hÓra, and Paul Gosling and published in 1999. What the enclosure was originally for, who built it, and when, remains unknown.