Ringforts, known in Irish as raths when constructed from earthen banks and ditches, were the most common form of rural settlement in early medieval Ireland, roughly from the fifth to the twelfth centuries. Thousands survive across the country in varying states of preservation, and Kerry, with its complex topography and relatively undisturbed land, holds a considerable share of them.

The rath at Crag belongs to this widespread but endlessly varied class of monument. In their original form, these enclosures typically surrounded a farmstead, protecting livestock and family from wolves and rival neighbours rather than serving any serious military purpose. The enclosing bank, sometimes reinforced with a timber palisade, and the external ditch defined a household's space, and in some cases souterrains, stone-lined underground passages used for storage or refuge, were built within. Without more detailed fieldwork records available for this particular site, the precise condition, dimensions, and any associated features of the Crag example remain difficult to characterise further.