Ring-ditches are the ploughed-down remnants of prehistoric burial mounds, or barrows, circular earthworks that once rose above the surrounding landscape as monuments to the dead. Where the mound itself has long since been levelled by centuries of cultivation, the ditch that originally encircled it can survive as a buried feature, showing up only when crops grow differently over disturbed ground, a phenomenon known as a crop mark.

The Knockbrack example sits within a recorded barrow cemetery, a cluster of such monuments sharing a common funerary landscape, catalogued in the Sites and Monuments Record as DU004-012. The site came back into focus in November 2021, when a drone aerial survey carried out by Ian Lennon captured imagery that revealed not just one but several ring-ditches within a large tillage field on the hill. The images were subsequently compiled into a formal record by Caimin O'Brien and uploaded to the national record in July 2023. Drone photography has become a quietly transformative tool in Irish field archaeology precisely because it can detect these buried outlines at the right time of year, when differential crop growth makes otherwise invisible features legible from above.

Knockbrack lies in north County Dublin, and the site sits within agricultural land that is actively worked, so access is not straightforward and permission from the landowner would be required before approaching the field itself. The ring-ditches are not visible at ground level in any conventional sense; the feature exists as a crop mark, meaning that the best view remains an aerial one, and the drone images recorded by Lennon are the most direct way to appreciate what is actually there. Those with an interest in the broader barrow cemetery of which this forms a part can cross-reference the SMR number DU004-012 through the National Monuments Service mapping viewer, which places the site within its wider archaeological context on the Knockbrack ridge.