A rath, in the broadest sense, is a roughly circular earthwork enclosure, typically defined by one or more banks and ditches, built during the early medieval period as a farmstead for a family of some local standing. They were places of daily life, of livestock and sleeping quarters and storage, rather than military strongholds, though their raised banks would have offered a degree of protection. This example in Carrowmore is one of many such monuments distributed across Mayo, a county whose Gaelic placename, Maigh Eo, meaning the plain of the yew trees, hints at an ancient, heavily worked landscape now largely stripped of the woodland that once defined it.

The name Carrowmore itself is anglicised from the Irish Ceathrú Mhór, meaning the big quarter, a townland designation referring to a traditional unit of land division. Such names, preserved in the modern map, often mark places where farming and settlement have continued more or less unbroken for over a millennium. Ringforts of this type were typically constructed between roughly the fifth and twelfth centuries, and in many parts of rural Ireland they have survived simply because later generations found it easier to plough around them than to demolish them. In other cases they endured through folklore, with local tradition associating them with the sídhe, the supernatural otherworld inhabitants of Irish mythology, making farmers reluctant to disturb them even when the original builders had long been forgotten.