The feature is a ring-ditch, a narrow, roughly circular trench cut into the earth, and this one is unusual in that it shows no evidence of an entrance gap anywhere along its circumference. Most enclosures of this kind preserve at least a break in the ditch where people or animals could pass through; the unbroken nature of this example sets it slightly apart and raises questions that the ground surface alone cannot answer.

Ring-ditches are found across Ireland and Britain and are generally associated with prehistoric funerary or ceremonial activity, though the term covers a range of features whose original purpose is not always clear from surface evidence alone. What makes the Rath Great example particularly interesting is its broader context. According to notes compiled by Tom Condit, it forms part of what archaeologists call a palimpsest, a landscape in which successive phases of human activity have been layered one over another, leaving traces of field systems and enclosures from different periods all overlapping in the same ground. The ring-ditch sits roughly 208 metres south-south-east of a nearby enclosure, and approximately 725 metres south-west of the Knockbrack ceremonial enclosure, a monument complex of considerable local significance. That clustering suggests this corner of north County Dublin was a focus of activity over a long stretch of time, with each generation leaving its own faint mark on the hillside.

The ring-ditch is not signposted, and access to the field would depend on the goodwill of the landowner, so it is worth bearing in mind that this is working agricultural land. For those who want to get a sense of the feature without setting foot in the field, it is clearly legible on Apple Maps satellite imagery from June 2018, where the circular crop mark or soil mark shows up well against the arable ground. The south boundary of the field, on the south-western slope of Knockbrack Hill, is the area to focus on. The surrounding landscape rewards attention too; given the density of recorded monuments in the vicinity, the low rises and field edges around Knockbrack carry considerably more archaeological weight than they might first appear to.