The site reveals itself as a cropmark, the kind of ghost that appears when soil moisture varies across buried features, causing growing crops to ripen or stress at slightly different rates above ditches and banks that no longer break the surface. What emerges, once the angle and altitude are right, is a roughly circular enclosure with three concentric fosses, each roughly ten to fifteen metres apart, giving the whole monument an overall diameter of around a hundred metres.

The site was first identified in oblique aerial photographs taken by Michael Moore on 22 July 2000. Those images showed the southern portion of the enclosure with reasonable clarity, while the northern arc fades considerably, possibly due to variations in soil depth or modern land use. A later look at satellite imagery from July 2018, noted by Simon Dowling, confirmed the cropmark was still legible under the right conditions. That same imagery hinted at something more complex still: the circular enclosure may itself sit within a larger sub-square enclosure, roughly 140 metres north to south, with rounded corners. The eastern side of this outer feature is not visible, but the southern, western, and northern portions appear in the imagery, suggesting the circular monument and whatever purpose it served may have formed one element within a more elaborate arrangement of boundaries or enclosures.

The function and date of the site remain unestablished. Triple-ditched circular enclosures of this scale are known from various periods in Irish archaeology, and without excavation it is not possible to say whether this one is prehistoric, early medieval, or of some other origin. What is clear is that the landscape at Clashwilliam is carrying considerably more history than its surface suggests.