The rath at Gorteendrunagh, in County Mayo, is one such site, a circular earthwork enclosure 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 an enclosure defined by one or more banks and ditches of earth, as opposed to a cashel, which uses stone, and thousands of them survive in varying states of preservation across Ireland.

Ringforts were the basic unit of rural settlement for much of early medieval Ireland, typically housing a single farming family and their livestock, with the enclosing bank offering protection against opportunistic cattle raids rather than any serious military assault. The place name Gorteendrunagh is itself worth a moment's attention: Irish townland names frequently encode older landscape features, land use, or personal associations, and the element "gort" generally points to a tilled field or enclosed cultivated ground, suggesting that the land around this site has been worked for a very long time. Mayo, with its mix of bogland, drumlin country, and Atlantic-facing terrain, contains a considerable concentration of such monuments, many of them sitting quietly in fields with no marker or public interpretation to draw the eye.