A fulacht fia is essentially a cooking or heating site, typically comprising a trough dug into the ground, a nearby water source, and a mound of heat-shattered stone built up over repeated use. Hot stones were dropped into water-filled troughs to bring them to the boil, and the cracked, blackened residue was raked aside each time, gradually accumulating into the horseshoe-shaped mounds that survive across the Irish landscape in their thousands.

What makes Kilpatrick particularly interesting is not one site but five, all apparently clustered within the same field. The main spread measures roughly twenty metres on its longer axis and ten metres across, and a very similar spread sits immediately adjacent to it. Three further spreads of the same character have been recorded in the same location, with a stream running to the west of the group. That proximity to water is typical; fulachtaí fia are almost invariably found beside streams, springs, or boggy ground, since a reliable water supply was central to however they were used. The concentration of five such sites in one small area is less typical, and raises questions that the physical remains alone cannot answer. Whether they represent activity spread across a long period, with one site being abandoned as the mound grew too large and another begun nearby, or whether some of them were used simultaneously, is not something the surface evidence can resolve.