The circular structure, roughly 70 metres in diameter, has left no trace at ground level. Its outline came to light in a single aerial image taken in May 1973, when the geometry of the underlying archaeology briefly registered against the dense moor-grass in a way that the human eye, standing on the hillside itself, simply cannot detect.

Circular enclosures of this kind are a familiar, if often poorly understood, feature of the Irish landscape. They range from the domestic to the ceremonial, and their true age and function frequently remain uncertain without excavation. What makes the Inchinanagh example quietly remarkable is how completely it has been absorbed back into the land. The aerial photograph, taken as part of a government survey, captured a cropmark or soil-mark, a differential in vegetation growth or ground colour that betrays the presence of a buried feature below. Beyond that single frame, the site offers nothing to the eye. There is no earthwork, no stone, no depression in the turf.