That changed in 1986, when an aerial photographic survey centred on the Bruff area caught the ring barrow at Ballynagranagh in a single frame, its circular form suddenly legible from above. Ring barrows are among the more modest expressions of prehistoric funerary practice, typically consisting of a low mound or level central area enclosed by a surrounding ditch, known as a fosse, and sometimes an outer bank. They are broadly associated with the Bronze Age, though many remain undated without excavation. What makes this one quietly remarkable is simply how long it went unrecorded, and how clearly the landscape had preserved it in plain sight.

The monument came to light as part of the Bruff aerial photographic survey of 1986, referenced under survey image Bruff 297 (AP4/3611). What the camera revealed was a circular earthwork approximately 27 metres in diameter, defined by a fosse and an outer bank. The site sits in improved wet pasture some 20 metres northwest of the Ballynamona River, a watercourse that also serves as the townland boundary between Ballynagranagh and Ballinlough. The low-lying ground is liable to flooding, which may partly explain why the earthwork was never ploughed out and survives in relatively good condition. Subsequent aerial and satellite imagery has confirmed its preservation: an Ordnance Survey orthoimage taken between 2005 and 2012, a Digital Globe image from 2011 to 2013, and a Google Earth capture from September 2020 all show the circular form clearly. A separate enclosure lies roughly 145 metres to the southwest, catalogued under the reference LI032-262, though its relationship to the barrow is not established. The record was compiled by Alison McQueen and Vera Rahilly and uploaded in November 2020.

The monument is on private agricultural land, and the surrounding ground is prone to waterlogging, so access is not straightforward and would require landowner permission. The site is best appreciated through aerial imagery rather than a ground-level visit, where the earthwork's defining fosse and outer bank may not be immediately obvious to an untrained eye standing in a wet field. Those with an interest in aerial archaeology, or in the way that heritage recording has shifted dramatically with the availability of satellite orthoimagery, will find the Ballynagranagh ring barrow a useful case study in how much can remain invisible until someone happens to look from the right angle.