Ringforts, known in Irish as raths or lios depending on their construction, were the most common form of rural settlement in early medieval Ireland, typically circular enclosures defined by earthen banks and ditches, and occasionally by stone walls. They served as farmsteads and protected enclosures for livestock, and tens of thousands of them once dotted the country. Most have been ploughed out or built over; those that survive often do so because local tradition discouraged interference with them, associating them with the fairy mounds of folklore.

The placename Castle Ffrench is itself worth a moment's attention. It points to the Ffrench family, a prominent Catholic landed family of Norman descent who settled in Connacht and whose name appears across the landscape of east Galway in various forms. The Ffrenches were among the so-called Tribes of Galway, the fourteen merchant and landowning families whose influence shaped the region from the medieval period onward. That a ringfort survives in association with a townland bearing their name suggests the site predates the family's arrival by many centuries, the early medieval earthwork and the later Anglo-Norman presence occupying the same ground across very different eras.