The one at Ballymarkahan in County Clare is a single example of a monument type that appears again and again in low-lying, waterlogged ground, easy to miss and easy to dismiss, yet representing a technology that endured for well over a thousand years. The name is sometimes translated loosely as "cooking place of the deer," though the original Irish is ambiguous, and scholars have long debated what these sites were actually used for.

The typical fulacht fia consists of a horseshoe-shaped mound of heat-shattered stone, usually surrounding or adjacent to a trough dug into the earth. The method reconstructed by archaeologists involves heating stones in a fire, then dropping them into a water-filled trough to bring the water rapidly to the boil. The broken, fire-cracked stones were discarded to the sides, building up the characteristic mound over repeated use. Most fulachtaí fia in Ireland date to the Bronze Age, broadly speaking the period from around 2000 to 500 BC, though some sites show evidence of use into the early medieval period. Their precise function remains open: boiling meat is the traditional explanation, but experimental and analytical work has raised the possibility that some sites were used for bathing, textile processing, or brewing. The Ballymarkahan example sits within a county that contains a considerable concentration of such monuments, Clare's mixture of boggy lowlands and river margins providing exactly the waterlogged conditions these sites seem to favour.