The one at Killard in County Mayo is among the quieter examples, a rath sitting in the landscape with little ceremony and, for now, little documentation attached to its name in the official record. A rath is a roughly circular enclosure, typically defined by one or more earthen banks and ditches, and built during the early medieval period as a farmstead for a family of some local standing. They were not military fortifications in any serious sense, more declarations of territory and status, the equivalent of a walled yard around a cluster of timber buildings where people lived, kept cattle, and worked the land.

Killard is a townland in Mayo, and the rath there belongs to a type of monument that was once ordinary, the everyday infrastructure of early Irish rural life from roughly the fifth to the twelfth century. Tens of thousands were built, and the fact that so many survive at all owes something to the folklore that grew up around them. Raths became associated with the sídhe, the supernatural inhabitants of the otherworld in Irish tradition, and farmers were often reluctant to disturb them with a plough or a digger, a superstition that served archaeology rather well. The Killard example sits within this broad tradition, a modest earthwork that has outlasted the society that raised it by more than a thousand years.