Known in Irish as a ráth, a ringfort is a roughly circular enclosure defined by one or more earthen banks and ditches, built primarily during the early medieval period, roughly between the fifth and twelfth centuries. They served as farmsteads, the everyday homes and working enclosures of rural families, and Ireland has tens of thousands of them, though many have been levelled by ploughing or development over the centuries. The fact that this one in Rehy has held on long enough to be recorded at all places it among the survivors.

Ringforts of this kind were the basic unit of settled life in early medieval Ireland. The enclosing bank offered a degree of protection for livestock against both human raiders and opportunistic predators, and the interior typically contained a dwelling house, outbuildings, and sometimes a souterrain, an underground stone-lined passage that could serve for storage or as a place of refuge. Clare is particularly well furnished with such sites, the county's varied terrain having preserved earthworks that flatter ground elsewhere has swallowed. The Rehy ráth belongs to this broader pattern of rural continuity, a landscape feature that predates the Norman arrival, the plantation era, and the townland system itself.