A fulacht fia is a type of prehistoric outdoor cooking site, typically identified by a mound of fire-cracked stones accumulated over years of use alongside a water-filled trough into which heated stones were dropped to boil the water. What came to light at Killoran was not one trough but two, the second cut directly into the fills of the first, suggesting the site was revisited and rebuilt rather than simply abandoned.

The site emerged only when topsoil was stripped away, as is common with fulachtaí fia that survive beneath accumulated bog. What lay underneath was a spread of burnt material roughly six metres by ten, covering a substantial sub-oval trough more than a metre deep, its fills containing wood fragments, sheep bone and teeth, and the scattered fire-cracked stones characteristic of this kind of site. At some later point, a smaller subrectangular trough had been cut into the same area, suggesting continued activity in the same spot. A wooden step preserved within the sandy trough fills was dendrochronologically dated, a method that establishes age by analysing tree-ring patterns in preserved timber, and placed the construction at 932 BC. That date puts the site firmly in the Late Bronze Age, a period when fulachtaí fia were in widespread use across Ireland. A second, related site lies around 150 metres to the south-east, raising the possibility that this stretch of low-lying, poorly drained land saw sustained use across a considerable span of time.