What looks like an ordinary drystone boundary running roughly north-east to south-east is, in fact, built directly over the remains of an Early Medieval ringfort, its stones incorporating and concealing what survives of a much older enclosing bank. The relationship between the two is not dramatic to the eye, but it captures something characteristic of the Irish countryside: centuries of human activity layered so closely together that the more recent simply absorbs the earlier.

A rath, to use the Irish term, was a circular enclosure defined by an earthen bank and typically a surrounding ditch, or fosse, used as a defended farmstead during the Early Medieval period, roughly the fifth to twelfth centuries. The Ardabrone example was never large; its interior diameter measured approximately twenty metres, making it a modest domestic enclosure rather than a seat of any great power. Today the site has been largely levelled, and the fosse has disappeared entirely at ground level. What remains is a bank of earth and stone, about two and a half metres wide and barely forty centimetres high on the interior, with the surviving stretch revetted on its inner face with large limestone boulders. Elsewhere, the line of the former bank can be read as a faint inward-facing scarp, no more than thirty centimetres high, tracing the south-west to north-west arc of what was once a complete circuit. The original entrance has been lost, absorbed into the general levelling that has reduced most of the enclosure to near-invisibility.

What gives the site its quiet interest is precisely this near-erasure. The drystone field wall built over the surviving north-east to south-east section has effectively fossilised that portion of the bank, preserving it beneath later stonework on a gentle south-east facing slope in open pasture. The limestone revetment on the interior face, still legible beneath and alongside the later wall, suggests that whoever built or maintained the rath had access to good local stone and used it deliberately to reinforce the bank from within.