These enclosures, known variously as raths or ringforts, were the standard form of rural settlement in early medieval Ireland, typically consisting of a raised circular bank of earth and a surrounding ditch, enclosing a farmstead and its outbuildings. Thousands survive across the country, and Kerry has more than its share, yet each one occupied a particular patch of ground for particular reasons, and the one at Crag is no exception.

The rath as a monument type belongs broadly to the period between the fifth and twelfth centuries, though many continued in use or accumulated layers of significance well beyond that. In Irish folk tradition, ringforts were frequently regarded as the dwelling places of the sí, the supernatural beings of older belief, which gave them a protective reputation that paradoxically helped preserve many from being levelled for farmland. Whether the example at Crag shared in any such local lore is not recorded, but the survival of these earthworks into the present is often as much a matter of social memory as agricultural inconvenience.