The field gives nothing away. Yet the earthwork surrounding it, a roughly oval ringfort measuring about 42 metres across its longest axis, is still legible in the landscape, its earthen bank rising to 2.4 metres and spreading nearly 4 metres at its base, even in its damaged condition.

Ringforts, known in Irish as raths when formed from earthen banks rather than stone, were the dominant settlement type of early medieval Ireland, broadly from the fifth to the twelfth century. Most enclosed a single farmstead, the bank and accompanying ditch forming a boundary that was as much about status and property as defence. The Kilphillibeen example follows the oval form common to the type, with its interior levelled by cutting into the hillside to the west, a practical piece of earthmoving that would have created a flat living area within the enclosure. Three gaps in the bank are visible, to the north-east, south-south-west, and east-north-east, with the north-east gap considered the most likely original entrance. A low terrace-like feature along the inner base of the western bank may simply be the result of the bank slumping over time rather than any deliberate construction.

The more intriguing element is the souterrain recorded in the interior. A souterrain is a stone-lined or rock-cut underground passage or chamber, typically associated with ringforts and thought to have served as storage space, a refuge, or both. This one has no visible trace remaining at the surface, its presence known through earlier investigation. The site sits in tillage land, and the combined pressures of cultivation and time have worn the whole complex down considerably, leaving a structure that rewards careful attention to the slight rises and dips of an otherwise ordinary-looking agricultural slope.