It is not the kind of setting that announces itself easily, but the earthworks, once noticed, are quietly legible in the landscape. A rath is a type of ringfort defined by an earthen bank and ditch rather than stone, and this one at Ballymahony was considered significant enough to be marked on Ordnance Survey six-inch maps in both 1842 and 1920, suggesting it was a visible and recognised feature across nearly a century of cartographic record.

The enclosure is subcircular in plan, measuring roughly 29 metres north to south and nearly 26 metres east to west on the interior, with the full earthwork extending to around 49 metres east to west at its maximum. An earthen bank, between five and seven metres wide, defines the circuit, and its outer face rises between one and 1.2 metres above the surrounding ground. Between the bank and what appears to be a fosse, or external ditch, there is a slight berm, a narrow level shelf that would once have helped stabilise the bank's outer edge. The fosse itself is now marked not by open water but by a boggy, rush-filled band two and a half to four metres across, the kind of soft, saturated ground that preserves the outline of a ditch long after the cut itself has silted and grown over. The interior sits roughly half a metre higher than the exterior, which is typical of the way rath interiors accumulate over time. The bank on the western side has been pushed inward and is noticeably more massive than elsewhere, while along the south it has flattened almost to a simple external scarp. These irregularities hint at later interference or collapse, and a separate piece of evidence reinforces that impression: an L-shaped depression, grass-covered and relatively shallow, cuts from the south-south-western part of the interior toward the centre and then turns eastward. The spoil from whatever activity created this feature appears to have been piled into the south-eastern quadrant, where the ground is still noticeably higher and uneven.