The one at Cahernalough, in County Clare, is a quiet example of a site type that continues to puzzle researchers. A fulacht fia typically survives as a horseshoe-shaped mound of burnt and shattered stone, usually found close to a stream or boggy ground. The prevailing theory is that these were prehistoric cooking sites, where stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, though some archaeologists have proposed alternative uses, from brewing to textile processing to bathing.

Most fulachtaí fia in Ireland date to the Bronze Age, roughly 1500 to 500 BC, though some have produced earlier or later dates. The shattered stone that forms the mound is the by-product of repeated heating and sudden cooling, which causes rock to crack and fragment. Over centuries, these discarded stones accumulate into the low, distinctive mounds that farmers and walkers occasionally stumble across today. The place name Cahernalough combines elements suggesting a stone fort near a lake, a reminder that this part of Clare preserves layers of activity from different periods, and that the fulacht fia sits within a wider landscape of prehistoric and early historic use.