The example at Carrowmore in County Mayo is one such site, a rath, which is the Irish term for a ringfort defined by an earthen bank rather than stone, typically enclosing a farmstead or the residence of a person of some local standing during the early medieval period, roughly between the fifth and twelfth centuries.

Ringforts of this kind were the basic unit of rural settlement for much of early medieval Ireland. A typical rath consisted of one or more circular earthen banks and ditches enclosing a central area where a family would have lived, kept animals, and stored food. The place name Carrowmore itself is an anglicisation of the Irish Ceathrú Mór, meaning the big quarter, a land division term common across Connacht, which suggests the area was significant enough in the medieval or early modern period to be named as a substantial portion of territory. Mayo, with its mix of bogland, drumlin country, and Atlantic coastline, contains numerous such earthworks, many of them poorly documented and easy to overlook against a landscape that has absorbed centuries of agricultural change.