The circular enclosure in the townland of Kilduff, County Limerick, is the kind of monument that reveals itself only from the air, and even then only faintly, as a ghost pressed into the soil.

The site was first identified during the Bruff aerial photographic survey of 1986, when a substantial circular cropmark appeared in survey image AP 4/3679. Cropmarks form when buried features, such as the ditches or banks of ancient enclosures, affect the growth of overlying crops or grass, making the outline of a long-vanished structure visible from altitude in certain light and seasonal conditions. The enclosure measures approximately 42 metres east-southeast to west-northwest and 28 metres north-northeast to south-southwest, suggesting an oval rather than perfectly round footprint. It sits on a gentle slope facing northwest, close to the boundary between Kilduff and the neighbouring townland of Mountcatherine. It was never recorded on any edition of the Ordnance Survey historic mapping, meaning it slipped through two centuries of systematic cartographic documentation entirely unnoticed. Later satellite imagery, including Digital Globe orthophotos from 2011 to 2013 and a Google Earth image from May 2017, confirmed the cropmark is still faintly legible, though the southern sector is disrupted where the road passes through it. The record was compiled by Alison McQueen and Vera Rahilly and uploaded in July 2020.

There is nothing to see at ground level. The enclosure survives only as a subsurface trace in what is now ordinary agricultural land, and no excavation has been recorded. The 1897 edition of the Ordnance Survey 25-inch map shows a backfilled quarry about 28 metres to the northwest, a reminder that this corner of Limerick has been worked and reshaped across many generations. For anyone curious enough to visit the area, the value lies less in the physical experience of the field than in the act of overlaying the aerial and satellite images against the present landscape, watching a buried outline reassert itself across the centuries in the pale differential green of a summer crop.