The rath at Carrowkeel in County Mayo is one such monument, a circular enclosure defined by an earthen bank and ditch, of the kind that served as a defended farmstead during the early medieval period, roughly between the fifth and twelfth centuries. The word "rath" refers specifically to this earthwork variety, as distinct from a "cashel", which is built from stone. Both types housed families of some local standing, their livestock kept within the enclosed space at night, the bank and ditch providing a degree of protection as much social as military.

Carrowkeel is a placename of Irish origin, derived from "An Ceathrú Caol", meaning the narrow quarter, a reference to a subdivision of land under the old Gaelic territorial system. Mayo itself is a county with a dense concentration of early medieval settlement remains, its boglands and pastures preserving earthworks that have survived precisely because they were never ploughed flat or built over. Without further specific detail available for this particular site, what can be said is that its presence in the landscape places it within a wider pattern of early Christian period habitation that shaped the rural geography of the west of Ireland in ways still faintly legible today.