The fosse, a flat-bottomed or V-shaped ditch that once defined its boundary, has been in-filled, its circuit erased from the ground. The only reason anyone knows it was there at all is that crops and soil behave differently over buried features, producing the faint tonal variations in aerial photography known as cropmarks. It was through exactly this kind of scrutiny of satellite imagery that Jean-Charles Caillère identified and reported the site.

The enclosure had, in fact, left a faint paper trail before that. The 1904 to 1905 edition of the Ordnance Survey six-inch map records the fosse across the south-east, south, and west sectors of the circle, along with a small pool, approximately 16 metres in diameter, sitting on the line of the fosse in the north-west sector. Whether that pool was a later feature or an original element of the enclosure's design is unclear, but its position suggests it occupied a hollow where the ditch once ran. By July 2019, satellite imagery still showed the fosse and the pool beneath a cover of vegetation. By September 2020, the vegetation had been cleared and the remaining fosse filled in, completing the erasure of a feature that had survived, at least partially, for well over a century on the map and considerably longer in the ground. Circular enclosures of this kind are found widely across Ireland and are often associated with early medieval settlement, though without excavation the date and function of any individual example remains open.