These horseshoe-shaped mounds of burnt and shattered stone, typically found close to water sources, are thought to date from the Bronze Age, and the one recorded at Cornagashlaun in County Mayo represents a quiet footnote in a very long story. The name fulacht fia translates loosely as "cooking place of the deer", and the prevailing theory holds that they were used for boiling water, either for cooking meat or, as some researchers have argued, for bathing, brewing, or textile processing. The method was straightforward: stones were heated in a fire, then dropped into a water-filled trough until the contents boiled. The cracked, heat-fractured stones were raked aside after each use, and over time these discards accumulated into the distinctive mound that survives today.

Cornagashlaun is a townland in the west of Mayo, a county that holds a considerable concentration of such sites. The landscape here, like much of the west of Ireland, is one of boggy ground and poorly drained pasture, precisely the kind of terrain where fulachtaí fia tend to cluster. The preservation of these monuments in upland and boggy areas owes much to the fact that such land was never intensively ploughed or developed, leaving the mounds more or less undisturbed since the Bronze Age. Without more detailed excavation records available for this particular site, it is difficult to say more about its specific dimensions, associated features, or precise dating, but its existence in this corner of Mayo adds to a picture of sustained prehistoric activity across a region often thought of as remote or marginal, but which was clearly well-settled and well-used long before the historical record begins.