Known in Irish as a rath, a ringfort is a roughly circular enclosure defined by one or more earthen banks and ditches, built during the early medieval period, broadly between 500 and 1000 AD. They served as farmsteads for families of some local standing, the banks offering a degree of protection for people, livestock, and stores. Tens of thousands of them once existed across Ireland; several thousand survive in varying states of preservation, scattered across fields and hillsides, some dramatically intact, others reduced to a faint rise in the grass that only aerial photography or a knowing eye can read clearly.

The example at Crag is one of Clare's quieter entries in that long catalogue. County Clare as a whole is well supplied with early medieval remains, owing in part to the relative stability of its pastoral land use over the centuries, which allowed earthworks to survive where tillage farming elsewhere destroyed them. The Burren to the north of the county is the most celebrated zone for such survivals, but ringforts appear throughout Clare, tucked into drumlin slopes, field corners, and gentle rises that would have commanded local views and drainage in equal measure. The specific history of this particular rath, its dimensions, whether it retains a souterrain (an underground stone-lined passage sometimes associated with such enclosures), and the extent of any surviving bank, remain details that have not been made publicly available in documented form.