The one at Cloncannon is the middle of this trio, with companions lying to both the west and east. That kind of clustering is not unusual in the Irish landscape, where ringforts, the circular farmstead enclosures of the early medieval period, roughly the fifth to twelfth centuries, tend to appear in groups rather than isolation, hinting at a settled agricultural community spread across the same terrain over generations.

The Cloncannon example is a fairly compact site, measuring 35 metres across in the north-south direction. It follows the classic rath form: a circular area defined by an earthen and stone bank, here about three metres wide, with a fosse, or defensive ditch, running outside it. The bank stands roughly half a metre above the interior ground level but rises a more imposing two metres on its outer face, a difference that reflects how the material dug from the fosse was piled outward to maximise the visual barrier to anyone approaching from outside. The fosse itself is three metres wide and survives to about 0.4 metres in depth. The entrance, a gap of eight metres, sits at the north-east, which is a commonly observed orientation for ringfort entrances across Ireland. The bank and fosse are best preserved along the southern and western arc, suggesting that the northern and eastern sections have suffered more from erosion or agricultural activity over the centuries.