This is a ring barrow, a prehistoric funerary monument typically consisting of a low central mound or flat area enclosed by a circular ditch and bank, used for burial during the Bronze Age and sometimes earlier. What makes this particular example quietly interesting is that it exists not as a visible earthwork but almost entirely as a ghost, readable only from the air.

The site came to attention through the Bruff aerial photographic survey of 1986, which flagged it as a possible enclosure under the reference Bruff 134. Aerial surveys of this kind work by detecting cropmarks, the subtle variations in grass or crop growth that occur above buried features, where soil disturbance from ancient ditches or banks affects how deeply roots can reach and how much moisture they retain. The circular cropmark at Coolalough, catalogued under the record number LI040-194001, was later confirmed on a Digital Globe orthoimage taken between 2011 and 2013, and again on a Google Earth image dated 20 September 2020. That second cropmark, a linear feature running east to west, intersects the circle at its southern edge and suggests additional buried activity in the surrounding ground. Related enclosures lie 95 metres to the west and 85 metres to the east, placing this barrow within a wider complex of features that the pasture above them does little to reveal. The record was compiled by Fiona Rooney and uploaded in June 2021.

There is nothing to see at ground level in the conventional sense. The field shows no obvious mounding, no earthwork, no standing stone. A visitor hoping to understand the site would do best to look at the aerial imagery available through the National Monuments Service or Google Earth before arriving, so that the approximate location of the cropmark can be oriented against field boundaries. The marks tend to show most clearly during dry summers, when moisture stress in the grass above the ancient ditch becomes visible from above. The surrounding landscape is low and open, and the nearby enclosure sites to east and west suggest this part of Coolalough repays patient, close attention to what lies just beneath the ordinary surface of things.