These sites, found in their thousands across Ireland, typically appear as horseshoe-shaped mounds of fire-cracked stone beside a natural water source. The basic principle was the same wherever they occur: stones were heated in a fire and dropped into a water-filled trough, usually timber-lined, bringing the water rapidly to a boil. The mound itself is the accumulated debris of that process, stones discarded after repeated heating and cooling had rendered them too fragile to use again.

Fulachtaí fia are among the most common prehistoric monuments in Ireland, with estimates running to many thousands of recorded examples. Most date to the Bronze Age, broadly spanning from around 2000 BC to 500 BC, though some sites show earlier or later activity. The name, loosely translated, refers to a cooking place associated with wandering bands or hunters, and the sites are often found in low-lying, boggy ground where water would have been readily accessible. County Mayo, with its wet upland terrain and extensive bogland, is well suited to their preservation. The one at Cornahavoley is noted as a monument in its own right, though the specific details of its dimensions, condition, and precise setting remain, for the moment, unrecorded in publicly accessible form.