It measures roughly 31 metres north to south and nearly 28 metres east to west, rising to about 1.85 metres at its highest point, with an opening just over 10 metres wide facing north-north-east. Two electricity poles now stand at its edge, a small collision of the ancient and the infrastructural that is more common across the Irish countryside than most people realise.

The mound is a fulacht fia, a term used for the characteristic burnt spreads left behind by prehistoric cooking sites. The typical interpretation is that water was heated in a trough by dropping fire-cracked stones into it; the discarded stones, fractured and blackened from repeated heating and cooling, built up over time into the distinctive kidney or horseshoe shape that survives today. The proximity of a stream to the south and a spring to the north-east would have made this location practical for exactly that purpose, providing a reliable water source close at hand. What makes the Lisballyhay example particularly notable is that it is not an isolated feature; it belongs to a cluster of four such monuments in the immediate area, suggesting repeated or sustained use of this small stretch of ground over a considerable period.