It was detected entirely through geophysical survey, meaning the ring-ditch, roughly 30 metres in diameter, remains below the surface, its outline revealed only through the subtle contrasts in soil and subsurface material that such surveys are designed to read. That a feature of this scale can sit quietly beneath a Dublin hillside, unexcavated and largely unknown, says something about how much of Ireland's prehistoric landscape is still, in effect, waiting.

The site came to light as part of the Discovery Programme's 'Late Iron Age and "Roman" Ireland' project, which used geophysical survey, conducted under Licence no. 13R084, to investigate sites across Ireland associated with the centuries around the turn of the first millennium. A ring-ditch is generally understood to be a roughly circular enclosing ditch, often interpreted as the remains of a burial monument or ceremonial enclosure, though the term covers a range of possible functions. This particular example sits within the southern quadrant of a hilltop enclosure already recorded in the archaeological register, and it is among the larger ring-ditches identified through the project. Inside the circle, the survey also detected smaller circular features and what are described as pit-type anomalies, suggesting further activity within the enclosed area. The findings were published by Dowling in 2015.

Because the site has not been excavated, there is nothing visible at ground level for a visitor to identify directly. The surrounding hilltop enclosure, however, is a real presence in the landscape at Knockbrack, and the broader elevated terrain gives some sense of why this location was significant to people in the Late Iron Age. Anyone interested in the survey data can consult the Discovery Programme's published findings, where the full geophysical results are discussed in their wider regional context.