The example at Carrowreagh in County Mayo is one such site, a rath sitting in the landscape of the west of Ireland with relatively little on record to explain it. A rath, in broad terms, is a circular enclosure defined by one or more earthen banks and ditches, built predominantly during the early medieval period, roughly between the fifth and twelfth centuries, and used as a defended farmstead by a family of some local standing.

Carrowreagh itself is a townland name with roots in the Irish "Ceathrú Riabhach", meaning something close to "the grey quarter", a reference to the colour or texture of the land rather than anything dramatic about its history. Mayo as a county is dense with such sites, the product of a farming society that organised itself around small, fortified enclosures across centuries of early Christian Ireland. Without more detailed fieldwork data attached to this particular monument, it is difficult to say whether the earthworks here are well-preserved or much reduced, whether the enclosure is a simple single-banked structure or something more elaborate. What can be said is that its presence in the townland places human settlement at Carrowreagh at least as far back as the early medieval period, and possibly earlier if the site reused older ground.