Beneath what is now the M4 motorway corridor in County Kildare, road construction in 2002 brought to light a small but telling trace of prehistoric activity: a fulacht fia, one of the thousands of ancient burnt mound sites scattered across the Irish countryside. A fulacht fia typically consists of a water-filled trough, a nearby hearth, and a mound of heat-shattered stone, the accumulated debris of repeatedly heating rocks and plunging them into water, possibly for cooking, bathing, or industrial processes. The example at Killickaweeny is modest in scale, but its component parts are legible enough to tell a coherent story.

The excavation, carried out under licence ahead of the Kinnegad-Enfield-Kilcock road development, uncovered a spread of blackened soil and charcoal that marked the site's footprint. At its centre was a sub-circular pit roughly 1.3 metres in diameter and just over a metre deep, almost certainly the trough where water was heated. Around its edges, archaeologists identified stake-holes and stone sockets, the remnants of some kind of timber or stone structure that once stood over or around the feature. A second, smaller and shallower pit to the east is thought to have served as the fire-pit or hearth, though no evidence of burning in place was found there. Both pits were filled with burnt stone and blackened soil, the classic signature of a fulacht fia in use. A short distance to the north-west, a further spread of clay and charcoal resisted easy interpretation, though it yielded one quietly interesting find: a flint scraper, recovered as the area was being cleaned back. Whether the scraper was connected to the fulacht fia or represented an entirely separate episode of activity on the same patch of ground, the excavation could not say.