Walk around its southern edge and you encounter a scarp, the steep inner face of the enclosure's bank, rising a solid 2.5 metres. Continue northward, uphill, and that same feature dwindles to barely a quarter of a metre. The fort does not diminish in importance as you move; it simply meets the slope on its own terms.

Ringforts, known in Irish as raths, were the most common form of rural settlement in early medieval Ireland, typically enclosing a family farmstead within a roughly circular earthen bank and external ditch. The Dooncaha example is oval rather than circular, measuring approximately 22 metres north to south and nearly 28 metres east to west. A fosse, that is an external ditch dug to reinforce the defensive character of the enclosure, survives along the north-western and north-north-eastern arcs, running to about 2.8 metres wide and 0.4 metres deep. The scarp itself, broadening to around 2 metres at its base, is best read at the southern end where the full height has been preserved. The record was compiled by Denis Power and uploaded to the national archaeological survey in August 2011, though the feature it describes is considerably older by many centuries.

The fort sits in pasture on a south-facing slope, and the interior, level despite the surrounding gradient, remains under grass. Two modern field boundaries have grown up alongside the ancient earthwork: one runs along the top of the scarp between the south-east and south-west, and another traces the western base of the scarp tangentially. These boundaries are worth looking for, since they can help orient a visitor trying to read the topography. The southern scarp, being the tallest and widest section, is the most legible part of the monument, and standing there, looking across the level interior, gives the clearest sense of the enclosed space that would once have been in daily use.