Rathmore, in County Mayo, contains within it the Irish word rath, meaning a ringfort, so the ringfort at Rathmore is, in a sense, a ringfort at the place named after a ringfort. That kind of layering is common across the Irish landscape, where early medieval earthworks were so embedded in daily life that they became the natural anchors for townland and settlement names long after the structures themselves fell silent.

Ringforts, also called raths, were the dominant form of enclosed farmstead in early medieval Ireland, built roughly between the fifth and twelfth centuries. They typically consist of a roughly circular area defined by one or more earthen banks and ditches, occasionally reinforced with stone, and were used as farmsteads and enclosures for livestock rather than as military fortifications in the conventional sense. Thousands survive across the country in varying states of preservation, and Mayo has a considerable concentration of them. The rath element in Rathmore suggests the site was prominent enough, or well-preserved enough, to define the locality around it. The qualifier mór, meaning great or large, implies the fort was of some notable size, though without more detailed survey information it is difficult to say more about its specific dimensions or construction.

The townland name, then, may be the most legible thing remaining about this particular site. That is not unusual for ringforts in agricultural lowlands, where centuries of ploughing, drainage, and land improvement have reduced many earthworks to faint cropmarks or erased them entirely. The persistence of the name, even where the physical form has been diminished, is itself a kind of record.