The raised circular area, roughly 30 metres in diameter, is enclosed by a low bank of earth and stone, and around part of it runs an external fosse, a shallow defensive ditch that would originally have reinforced the enclosure's boundary. What gives this particular rath its mild air of puzzle is a feature inside: some 12 metres from the eastern bank, a low terrace or step runs north to south across the interior. Its purpose is not recorded, and it is the kind of detail that invites speculation without quite settling into an answer.

Ringforts of this type, known variously as raths or lios, were the dominant form of rural settlement in early medieval Ireland, from roughly the fifth to the twelfth century. They served as enclosed farmsteads, their banks and ditches marking territory and providing modest security for a family and their livestock rather than functioning as military fortifications in any serious sense. At Frankford, the fosse is best preserved on the upslope western half of the monument, where it measures 3.5 metres wide and survives to a depth of 0.7 metres, while it has largely disappeared elsewhere, smoothed out by centuries of agricultural use or natural erosion. The original entrance can no longer be identified. Intriguing too is a local tradition of a souterrain, an underground stone-lined passage typically associated with storage or refuge, located around 400 metres to the south-west of the ringfort. Whether the two features were ever connected in use, or simply belong to the same broad period of settlement activity in the area, is not known.