Francis Macken noticed it from his tractor seat: a broad ring of darker, lusher grass set against a background of stunted, lighter growth in the field his family had long called the kiln field. Cropmarks of this kind appear when buried ditches or disturbed soils retain more moisture than the surrounding ground, causing the grass or grain above them to grow differently, and they are often only visible during prolonged dry spells when the contrast becomes sharp enough to read. Macken enlisted his nephew Warren, and together they commissioned a drone survey from Drone Services Ireland, which confirmed the outline and revealed that the field contained several other buried features besides.

The monument, recorded and compiled by Margaret Keane in December 2018, is a sub-circular enclosure measuring 44 metres east to west and 43 metres north to south internally, with a fosse, that is a surrounding ditch, running around it at 2.8 metres wide. A rath is the Irish term for a ringfort, a type of enclosed farmstead used throughout early medieval Ireland, typically defined by one or more earthen banks and ditches. The squared corners at the north, east, and south give this example a slightly unusual character, and the entrance causeway at the east-south-east is a clear 3.8 metres across where the fosse terminates in sharp linear ends. Inside the eastern portion of the enclosure, a rectangular cropmark measuring roughly 15 metres by 5 metres may represent the footprint of a structure. The site sits on a south-facing slope below a ridge that rises to the north-north-east, a position that would have offered extensive views southward toward the Dublin mountains and a clear sightline east to Knockbrack hill, where barrows from a known cemetery are visible on the horizon.

Because this is a cropmark site rather than an upstanding earthwork, there is nothing visible at ground level during most of the year; the enclosure exists as a pattern in the soil rather than as banks or ditches you can walk around. The surrounding field remains agricultural land, so access would require landowner permission. The broader landscape context is worth bearing in mind: the field contains multiple other ring-ditches and linear features, some possibly connected to the ringfort and some perhaps representing entirely separate activity from different periods, and the Knockbrack barrow cemetery to the east adds further depth to what is already a remarkably layered corner of north County Dublin.