A causewayed entrance, roughly six metres wide, opens through the bank to the north-north-east, and from there a flanked avenue of similar width extends outward for twenty-eight metres, earthen banks rising to either side of the approach. This is not a feature you commonly find at a rath, the term used for the circular earthen enclosures, typically of early medieval date, that were built as enclosed farmsteads across Ireland. The avenue lends this particular example something almost ceremonial in its layout, though what practical or social purpose it served is a question the ground alone cannot answer.

The enclosure itself is substantial: roughly eighty-six metres across, bounded by an earthen bank that stands about a metre high on the interior and slightly more on the exterior, with an external fosse, or ditch, running around it. The fosse is mostly broad and shallow, but to the west it narrows and deepens noticeably, a variation that may reflect later disturbance or original design intent. One section of the south-south-west side has been lost entirely, the bank gone and the fosse cutting inward into the interior, though an Ordnance Survey six-inch map from 1935 and an earlier record by a researcher named Lee both show the circuit intact at that point, placing the damage sometime after the mid-twentieth century. Lee, writing in 1932, described it as a particularly fine rath in fairly good preservation, a judgement that now requires some qualification given subsequent deterioration.

The site sits on a gentle north-north-east-facing slope at the northern edge of Johnson's Wood in Castleblagh, and the interior slopes down in the same direction. It is heavily overgrown with a mixture of coniferous and deciduous trees, which at once obscures the earthworks and, in some respects, protects them from further erosion. The avenue and entrance to the north-north-east are the features most worth seeking out, as they give the clearest sense of the original form and the unusual degree of elaboration that made this enclosure worth noting in the first place.