The site sits roughly 80 metres north of the townland boundary with Castlelloyd, within an existing field system, and its absence from the standard cartographic record means it slipped through generations of official documentation entirely unnoticed.

The enclosure came to light through aerial photography carried out as part of the Bruff aerial photographic survey in 1986, where it was catalogued as Bruff 20.1. That survey image revealed a roughly oval earthwork measuring approximately 44 metres north to south and 48 metres east to west, making it a substantial feature of the kind typically associated with early medieval settlement in Ireland. Circular enclosures, often called ringforts or raths, were the dominant form of rural farmstead from roughly the fifth to the twelfth centuries, enclosed by an earthen bank and ditch to protect livestock and family. What makes Garryduff particularly interesting is the presence of three smaller circular features visible within the enclosure interior on the aerial photographs, each around 6 metres in width, labelled Bruff 20.2 to 20.4. These internal features may represent the remains of individual structures, such as roundhouses, or alternatively they could be ring-barrows, which are low burial mounds surrounded by a circular ditch. The distinction matters considerably, and it remains unresolved. The site's visibility has since been confirmed on the Ordnance Survey Ireland orthoimage from 2005 to 2012, Digital Globe imagery from 2011 to 2013, and a Google Earth image taken in November 2018, compiled into a formal record by Edmond O'Donovan and uploaded to the national record in September 2020.

The enclosure sits on private agricultural land and is not formally accessible to visitors, but its outline can be examined through freely available satellite imagery, where the circular earthwork reads clearly as a crop or soil mark against the surrounding pasture. It lies around 100 metres west-northwest of a separate enclosure in the same landscape, suggesting this part of Coonagh Barony once held a cluster of activity that has left almost no trace above ground except from the air.