Fitted into the southern edge of what is an early medieval earthwork is a horse-shoe shaped limekiln, a structure that belongs to an entirely different era and set of priorities. Limekilns were used to burn limestone at high temperatures, producing quicklime for agricultural improvement and building mortar, and they were a common feature of the Irish countryside from the seventeenth century onwards. That someone chose to build one directly into the scarped bank of a ringfort says something practical about how these ancient monuments were viewed by later generations: not as sacred remnants to be avoided, but as convenient ready-made earthworks, offering shelter and structure for whatever work was at hand.

The Archaeological Survey of Ireland recorded the site in 2000, and what they found was a raised circular area roughly twenty metres in diameter, defined by a scarped edge rising to about 1.4 metres and ringed by an external fosse, the term for the ditch that typically surrounds a rath, here measuring around 3.4 metres wide and just over half a metre deep. Ringforts of this kind, known in Irish as raths when defined primarily by earthen banks rather than stone, were built across Ireland during the early medieval period, broadly from around the fifth to the twelfth century, and functioned as enclosed farmsteads for a single family or small community. The Knocknagranshy example is modest in scale but intact enough in outline to be legible. A modern entrance ramp, six metres wide, was added at the eastern side, and a field boundary cuts across the monument at the west, the kind of agricultural interruption that accumulated over centuries without anyone necessarily intending to diminish the structure.

The site sits in level pasture immediately south of a public road, with open views in all directions, so the approach is straightforward and the surrounding landscape easy to read. The interior was recorded as densely overgrown in a Google Earth image from June 2018, so visitors should expect vegetation rather than clear ground. The limekiln built into the southern bank is the detail worth looking for; its horse-shoe shape, measuring roughly 9.4 metres north to south and 6.5 metres east to west, is substantial enough to be distinguishable from the natural rise of the earthwork if you know to look for the curve of its walls against the older scarp.