The example at Duncummin in County Tipperary follows that general form, but only just. What was once a neat circle of earth has been worn, eroded, and otherwise reshaped by centuries of exposure until it now presents as a D rather than an O, its eastern side flattened back into a straight edge where the surrounding scarp has gradually retreated.

The mound sits on top of a broad, gently sloping rise in undulating pasture, giving it a position that would once have been locally visible for some distance. The raised interior measures roughly 16 metres north to south and 10 metres east to west, enclosed by an earthen scarp about 1.4 metres high on the outside. Around much of the circuit there is a flat-bottomed fosse, the term for the encircling ditch, roughly 2.1 metres wide at its base, and beyond that a low broad outer bank, modest in height but spreading nearly 5 metres across. From the north-north-east round to the south-east, however, both the fosse and the outer bank have disappeared entirely, leaving only the eroded scarp that creates the present straight edge. Where the fosse once ran on the north-north-east side, a shallow circular pond now sits, roughly 10 metres across and no more than half a metre deep, occupying the line of the original ditch as though water found a memory of the old hollow and settled there. On the south-eastern arc of the outer bank, a standing stone has been placed or has long stood on the crest, adding a second layer of prehistoric interest to what is already a quietly complex site.