What they were avoiding was a cluster of three ring-ditches, circular earthwork features typically associated with prehistoric burial or ceremonial activity, ranging in diameter from roughly five to twelve metres. The fact that the enclosure seems to accommodate rather than overwrite them suggests these earlier features were still visible, perhaps still meaningful, to the people who came later.

The site at Knockbrack came under investigation as part of the Discovery Programme's 'Late Iron Age and "Roman" Ireland' project, which used geophysical survey, conducted under Licence no. 13R084, to examine sites across the country without breaking the ground. Ring-ditches of this kind, circular trenches that once surrounded a central burial mound or flat grave, are a fairly common signature of Bronze Age or Iron Age funerary landscapes across Ireland, though they are rarely preserved well enough to be studied in such close relation to a later enclosure. At Knockbrack, the three ring-ditches visibly overlap one another, which indicates that the area was returned to over multiple periods, with new features cut into or beside earlier ones. This layering of activity, noted by Dowling in 2015, is what makes the cluster particularly interesting to archaeologists trying to understand how such places were used and reused across centuries.

The site sits north of the hilltop enclosure recorded as DU004-012006, and much of what is known about it comes from that geophysical survey rather than excavation, meaning the ground itself remains unbroken and the full picture is still being pieced together from subsurface anomalies. Visitors to the Knockbrack area should be aware that features like these are rarely signposted or obvious at ground level; ring-ditches are most legible from the air or through survey data. What can be appreciated on foot is the broader topography, the way the hillside holds its layers of use quietly, one era folded into another without much ceremony.