These low, horseshoe-shaped mounds of fire-cracked stone are among the most common archaeological monuments in Ireland, typically Bronze Age in date, and are thought to have functioned by heating stones in a fire and dropping them into a water-filled trough to bring it to a boil. The one at Lecarrow in County Mayo came to light not through deliberate excavation but through the routine cutting of a drainage channel through the bog at Park, which sliced cleanly through the deposit and left its contents exposed in section.

What the drainage channel revealed was modest but legible: a layer of burnt stone and charcoal running some 8 metres in length and no more than 0.25 metres thick, lying between 0.1 and 0.25 metres below the present surface of the bog, with roughly 0.65 to 0.7 metres of peat beneath it before the underlying boulder clay begins. The stones themselves are small, almost all under 0.1 metres in their longest dimension, and the charcoal is concentrated towards the base of the layer, which is consistent with ash and embers settling downward over repeated use. Geophysical survey confirmed that the feature is a very slight one, which matches the thinness of the visible deposit. What makes the location particularly striking is not this site in isolation but the cluster it belongs to: a second fulacht fia was found just 18 metres to the south-east, exposed in the same drainage channel, and a third lies roughly 94 metres to the north-east, all within the same broad peat basin. Three such sites in such proximity suggests sustained, repeated activity in this part of the landscape over a considerable period, even if no single visit leaves much of an impression now.