A fulacht fia, in its simplest form, is a burnt mound, the accumulated debris of a cooking or heating method that involved dropping fire-heated stones into a water-filled trough until the water boiled. The stones, cracked and spent after repeated use, were raked aside into a mound, and over centuries of use those mounds could grow to a considerable size. They are found most often in low-lying, wet ground near streams or springs, and their horseshoe or kidney shape, formed as material was cast to either side of the trough, is usually the first thing to catch the eye.

Most fulachtaí fia in Ireland date from the Bronze Age, broadly between 1500 and 500 BC, though some have been shown through excavation to belong to earlier or later periods. The precise function of individual sites has been debated for decades. Cooking is the explanation that held sway for the longest time, and it remains plausible, but experiments and analysis have also raised the possibility that some sites were used for bathing, textile processing, or brewing. In most cases the archaeology alone cannot settle the question, and sites like the one at Dromultan carry that ambiguity quietly into the present. Kerry has a dense concentration of these monuments, a reflection of both the county's wet terrain and the intensity of Bronze Age settlement across the southwest of Ireland.