It measures roughly 30 metres across, it is almost certainly made of stone, and it has gone entirely unnoticed by most people who have ever walked above it. No walls protrude, no signage marks the spot. The only reason anyone knows it is there at all is because of what a geophysical survey revealed in the soil.

A geophysical survey, which uses instruments to detect buried features by measuring changes in the ground's magnetic or electrical properties without disturbing the surface, was carried out under licence number 05R0137 and published by Nicholls and Shiel in 2005. Their findings identified the circular enclosure at a depth consistent with long burial, its stone fabric surviving as an anomaly in the data rather than as anything visible. Circular enclosures of this kind are a recurring feature of the Irish landscape, ranging from the large ceremonial ringforts of the early medieval period to smaller enclosures of uncertain date and function. Without excavation, it is not possible to say precisely what this one was, when it was built, or who built it. The survey result alone places it on the record.

There is nothing to see at Clonard in the conventional sense. The enclosure lies below ground on private agricultural land, and the site carries no visitor infrastructure. What the record offers instead is a different kind of attention: knowing that a 30-metre stone circle is present in this landscape, invisible from any angle, changes the quality of looking at an otherwise ordinary field. For anyone interested in landscape archaeology or the buried texture of the Dublin countryside, the published survey data held through the National Monuments Service is the most practical point of entry. The site was compiled into the record by Christine Baker and uploaded in February 2015, part of the slow, methodical work of making Ireland's subsurface geography legible.