The one at Lackareagh Beg, in County Clare, is a quiet example of a site type that has puzzled archaeologists for generations. A fulacht fia typically appears as a horseshoe-shaped or kidney-shaped mound of cracked, fire-shattered stone, usually found close to a water source. The prevailing theory is that these were ancient cooking sites, where stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, though other uses, from textile processing to bathing, have also been proposed. Most date to the Bronze Age, roughly 1500 to 500 BC, though some examples fall outside that range.

Lackareagh Beg itself is a small townland in Clare, a county with a particularly dense concentration of prehistoric remains, owing in part to the Burren's remarkable ability to preserve ancient features in its thin, rocky soils. The burnt mound here represents the accumulated debris of repeated use, each heating and cooling cycle causing stones to fracture and become useless, so that they were discarded and new ones fetched. Over time, this waste material built up into the distinctive mound that marks the site today. That such an ordinary, functional object, essentially the remnants of a very old kitchen, has survived into the present is one of the quieter surprises of the Irish archaeological landscape.