That gradual merging of the early medieval and the agricultural is part of what makes these sites so quietly interesting: the land never stopped being used, and the ringfort simply became a convenient edge.

A rath, as this type of earthwork is known, was typically a circular enclosure defined by an earthen bank and an outer ditch, used as a farmstead and sometimes a place of modest status during the early medieval period in Ireland, roughly between the fifth and twelfth centuries. At Derraghan Beg, the circular area measures 48 metres in diameter, enclosed by a low bank of earth and stone roughly 3.9 metres wide and now only about 0.3 metres high. Outside it lay a fosse, the shallow external ditch that would have reinforced the bank's defensive or boundary function, measuring around 3.1 metres wide and 0.4 metres deep where it still survives. That survival is partial: along the western and north-western arc, the fosse has been deepened over time and pressed into service as a field drain, while along other stretches both bank and fosse have been levelled almost entirely. Sections of the bank from the west-south-west around to the north, and from the east around to the south-east, have been incorporated into field boundaries, folding the prehistoric structure into the pattern of land division that surrounds it today. The original entrance to the enclosure is no longer recognisable.