The detail is easy to miss, but it is the kind of thing that makes this particular ringfort quietly compelling, even in its current state of near-inaccessibility beneath dense overgrowth.

Ringforts, also known as raths, are roughly circular enclosures defined by earthen banks and ditches, built predominantly during the early medieval period in Ireland as farmsteads or places of habitation for a family and their livestock. This one on an east-facing slope in Killavallig is a double-ramparted example, meaning it has two concentric earthen banks with a fosse, or ditch, running between them. A survey carried out by Bowman in 1934 recorded the fort at approximately 49 yards in diameter, with the outer rampart already showing signs of attrition at that point; roughly one-third of it had been levelled, while the remaining section stood about five feet high and eight feet wide. The inner rampart was lower, around three feet. The fosse between them measured some twelve feet across, and the streamlet that runs around half its circuit was already a noted feature of the site at the time of that survey. The current diameter is recorded at approximately 40 metres, suggesting some continued erosion or simply the imprecision of different measuring methods across the decades.