What makes it quietly interesting is not what survives but what the remains reveal about the density of early settlement in this corner of the Iveragh Peninsula: this cashel, a type of stone-walled ringfort typically associated with early medieval farming families, is just one of four such enclosures clustered together on these same hillside slopes.

The site measures approximately 20 metres across on its north-east to south-west axis and just over 23 metres on its north-west to south-east axis. A field boundary running north-west to south-east cuts directly through it, bisecting the interior, and two further field walls branch off from this across the enclosure, meaning that the original form of the cashel has been overlaid and disrupted by later agricultural activity. Despite this, something of the original construction is still legible. At the north-west, the wall retains faced courses of large boulder-like slabs and stands 1.45 metres wide, while at the south-east, where a small stream runs along the edge of the site, the wall rises to 2.1 metres in height on its exterior face, significantly taller than the average of around one metre elsewhere along the circuit. Inside the south-west sector, a small stony mound roughly 2.8 metres in diameter may be the collapsed remains of a hut, which would have been the kind of modest structure a single household once occupied within the protected enclosure of the cashel wall. The grouping of four cahers on Coomduff suggests that this was once a more populated and organised agricultural landscape than the quiet hillside now implies.