Rathpeacon contains the Irish word rath, the term for a ringfort, an enclosed farmstead of the early medieval period typically defined by one or more circular earthen banks, and the fact that the settlement type is baked into the place name suggests this enclosure was prominent enough in the landscape to anchor local identity for over a millennium. Today it sits quietly in pasture on an east-facing slope, its outline still legible but softened by centuries of grazing and weather.

The fort is roughly circular, measuring 58 metres north to south and 55.5 metres east to west, which puts it at a fairly substantial size for a rath. Ringforts of this kind were the dominant settlement form in Ireland from roughly the sixth to the tenth centuries, and thousands survive across the country in varying states of preservation. What defines this particular example is a combination of features: a low rise running from the south-west to the south-east marks part of the perimeter, while a stone-faced earthen field fence completes the circuit from the south-east back round to the south-west. That stone-facing is worth noting, since it suggests at least some deliberate construction effort rather than a purely earthen bank, though the overall impression now is of a landscape feature that has been quietly absorbed into ordinary agricultural use.