What makes it worth a second look is not its scale but its layered geometry: this is not a simple ring but a structure that combines several different defensive or enclosing elements arranged around a central space measuring approximately 33 metres east to west and 27.5 metres north to south.

A ringfort, or rath, is an early medieval enclosed farmstead, typically dating from roughly 500 to 1000 AD, built to define and defend a family's living and farming space. This example in Ardyhoolihane is defined by an internal bank rising about a metre in height along its western to north-eastern arc, with a lower external bank, around half a metre high, running from the north-west to the north-east. To the north-east and around to the west, a scarp, essentially a deliberately shaped slope cut into the drumlin itself, rises to 1.7 metres and follows the line of the inner bank. Between the external bank and this scarp, there is an intervening fosse, a defensive ditch, roughly 0.7 metres deep and 7 metres wide, running from north-west to north-east. Gaps in the inner bank to the north and north-west likely indicate original or later entrance points, while breaks in the scarp to the east, east-south-east, and south-east suggest further interruptions, possibly also original openings or later erosion. The combination of bank, counterscarp, and fosse gives the site a more complex defensive profile than many simpler raths across the Irish countryside.

The drumlin setting is itself significant. Drumlins, the smooth elongated hills shaped by glacial action, were frequently chosen for ringfort construction, offering natural elevation and clear sightlines. Here, that elevation carries the eye out over Bantry Bay, which would have made the site useful for monitoring movement across water as much as across land.