The example at Castletown in County Sligo has lost that feature entirely, at least as far as surface evidence goes, which gives it a quietly confusing quality. The bank itself survives, a roughly circular platform of earth some twenty-three metres across from north to south and twenty-two metres east to west, rising only about seventy centimetres above the interior ground level and spreading to a width of over six metres. The original entrance, the gap through which people, animals, and goods once passed in and out of a family's defended farmstead, is no longer identifiable.

Ringforts, sometimes called raths, were the most common form of rural settlement in early medieval Ireland, typically enclosing a farmstead occupied by a single family and their livestock. They were defined by an earthen bank, occasionally supplemented by a timber palisade, and a surrounding ditch. What makes Castletown's example particularly interesting to look at closely are two short lengths of relic field bank that abut the outer face of the main enclosure, one at the north-west and one at the south-east. Each segment runs about five metres in length and stands roughly a metre high. These remnants suggest that the ringfort was once integrated into a broader pattern of field boundaries, the kind of organised agricultural landscape that extended outward from a farmstead into the surrounding land. The field system has largely gone, but these two abutting stubs preserve a faint outline of how the site once connected to a working countryside rather than sitting in isolation.