What survives is a rath, a type of ringfort defined by an earthen bank or, as here, a scarp, which is an abrupt slope cut into the ground to mark the perimeter of what would once have been an enclosed farmstead, most likely dating to the early medieval period in Ireland, roughly between the fifth and twelfth centuries. The scarp at Kilcornan measures between one and a half and two metres in height and describes a near-circular shape, roughly twenty-five metres across, enough to have sheltered a household and its associated structures within.

By the time the monument was formally described in 1971, and again in 1976, the enclosure had already suffered considerable damage. The southern portion had been quarried, a common fate for earthworks that sit on slightly elevated ground and offer convenient material for field drainage or road repairs. The interior tells a similarly complicated story: a small earthen mound in the south-western quadrant and further disturbance in the north-eastern quadrant are both attributed to modern interference rather than any original feature of the site. What that interference consisted of is unrecorded, but the result is a monument that reads, on the ground, as a partial and altered thing, its original form only partially legible beneath the cumulative effects of agriculture and extraction.