They appear as low, horseshoe-shaped mounds, typically found near water, and represent the remains of ancient cooking sites, possibly also used for bathing, dyeing, or brewing. The basic method involved heating stones in a fire, then dropping them into a water-filled trough to bring it to a boil. Over time, the cracked and spent stones accumulated into the characteristic mound that archaeology has learned to recognise. The one recorded at Baile An Lochaigh, in County Kerry, is one such site, quietly occupying its place in a county that holds a remarkable concentration of prehistoric remains.

Most fulachtaí fia date to the Bronze Age, roughly between 1500 and 500 BC, though some have been found with earlier or later associations. Kerry, with its boggy ground and abundance of streams, provided ideal conditions both for their original use and for their preservation. The waterlogged, acidic soil that makes much of the county difficult to farm has, over millennia, done a reasonable job of protecting what earlier populations left behind. The specific history of the Baile An Lochaigh example remains to be fully documented, but its presence adds to a broader pattern of Bronze Age activity across the Iveragh and surrounding areas, where mounds of fire-cracked stone turn up in field margins, beside ditches, and at the edges of low-lying ground with quiet regularity.