It does not announce itself with stonework or a raised mound, and for most of recorded cartographic history it went entirely unnoticed, absent from the Ordnance Survey Ireland maps that catalogued so much of the Irish landscape in careful detail. What lies here in the townland of Ballynagreanagh is a barrow, a prehistoric burial or ceremonial monument, and it is known to exist only because a camera attached to an aircraft happened to pass overhead at the right moment.

The site was identified during a Bruff aerial photographic survey in 1986, when it appeared in the archive as reference Bruff 61, AP 4/3616, a roughly circular cropmark visible from altitude but invisible to anyone walking the field below. Cropmarks form when buried archaeological features, such as the filled ditches or compacted ground of a long-vanished mound, affect how vegetation grows above them, producing faint differences in colour or height that only become legible from the air, particularly during dry spells. The barrow sits in wet pasture roughly 125 metres west of a watercourse that runs along the townland boundary with Knockderk, placing it within a wider prehistoric landscape. Some 155 metres to the northwest lies a fulacht fia, a type of ancient cooking site typically identified by a horseshoe-shaped mound of fire-cracked stone beside a former water source, dating in Ireland most commonly to the Bronze Age. The barrow falls within a recorded field system as well, suggesting that this corner of County Limerick was once a purposefully organised and inhabited place. The circular cropmark has remained consistently visible on Ordnance Survey orthophotos taken between 2005 and 2012, and on a Google Earth image dated 20 September 2020, compiled as part of a record uploaded by Martin Fitzpatrick in March 2021.

The monument has no formal public access, and because it sits in private agricultural land, any visit would require the landowner's permission. There is nothing to see at ground level in the conventional sense; the feature exists, for practical purposes, as an aerial phenomenon. Those with an interest in the site are best served by examining the orthoimages available through the National Monuments Service record, where the circular outline reads clearly against the surrounding pasture. The nearby watercourse and the broader field system provide some orientation for understanding how the barrow once related to its landscape, even if that relationship is now largely a matter of inference from shadows seen from above.