The enclosure at Ardenagh Great is visible only as a cropmark, a circular outline roughly thirty metres across that appears when crops or grasses grow unevenly over buried ground disturbance. The slight fosse, or ditch, that once defined this circular area has long since been filled in or eroded away, but differential moisture retention in the soil means that, from the air or on aerial imagery, the ring still traces itself out across the slope.

The site sits near the top of a south-east-facing slope on a low ridge running north-east to south-west. That position, elevated and outward-looking, is typical of enclosures of this kind across Ireland, where a modest rise offered both practical advantage and a degree of visibility across the surrounding land. The enclosure was first reported by Jean Charles Caillére, and the record was later incorporated into the Archaeological Inventory of County Wexford, published in 1996. The cropmark itself has been confirmed through aerial imagery on more than one occasion, appearing on Map Genie coverage from 2005 to 2012 and again on iMAPs imagery from 2022, suggesting the underlying feature is sufficiently consistent to register across different seasons and conditions. Whether it represents a ringfort, a burial enclosure, or some other form of defined space is not established from what survives at the surface alone, but the circular form and single fosse are characteristic of early medieval settlement enclosures found throughout the Irish landscape.