It measures 26 metres across in both directions, a near-perfect circle defined by an earthen bank still standing to almost two metres in height, with a fosse, or defensive ditch, running around the outside. On the inner face of the bank, sections to the south-west, west-north-west, and north retain their original stone facing, a detail that speaks to the care originally put into its construction and the degree to which the structure has endured.

Ringforts, known in Irish as raths when earthen rather than stone-built, are among the most common archaeological monuments in Ireland, with tens of thousands recorded across the country. Most date to the early medieval period, roughly the fifth to twelfth centuries, and functioned primarily as enclosed farmsteads for a single family or small community, the bank and fosse providing both a physical boundary and a degree of social status. The Rea example follows this familiar plan, with a south-facing entrance 5.5 metres wide and a causeway crossing the fosse. What gives it a particular point of interest is the rectangular depression running almost 18 metres north to south down the centre of the interior, only 2 metres wide and 0.4 metres deep. The mound of material in the north-west quadrant may well have come from the digging of that depression, though what the depression itself originally served, whether as a souterrain trench, a drainage feature, or something else entirely, is not recorded. The cattle gaps cut through the bank at various points are a reminder that this ancient enclosure has been folded, for a very long time, into ordinary agricultural life.