In Irish placename convention, "rath" denotes a ringfort, one of those circular earthwork enclosures that dot the Irish countryside in their thousands, raised during the early medieval period, roughly between the fifth and twelfth centuries, as the defended farmsteads of prosperous farming families. That the townland itself is named after one suggests this particular example was prominent enough, or enduring enough, to anchor the local geography for generations.

Ringforts of this kind were typically formed by one or more concentric banks of earth and ditches enclosing a roughly circular area, within which a family would have kept their dwelling, outbuildings, and livestock. The more elaborate examples, built in stone, are known as cashels or cahers, while the earthen variety falls under the broader category of rath. They were not primarily military structures in any grand sense, more a practical combination of boundary marker, status symbol, and protection against opportunistic cattle raids, which were a routine feature of early Irish rural life. The Rathmore example, sitting within a landscape whose very name preserves its presence, belongs to this widespread but individually significant tradition.