A fulacht fia, the most common prehistoric monument type in Ireland, was essentially an outdoor cooking facility: a trough dug close to a water source, filled with water, and heated by dropping fire-cracked stones into it until the contents boiled. The stones, once fractured and spent, were raked out and piled around the trough's edges, forming the curved mound that survives today. At Ceapaigh Na Gcrann, on the lower western slopes of a ridge dividing Derriana and Cloonaghlin loughs in south Kerry, you can see exactly this process preserved in cross-section; the composition of at least one mound is openly visible, its interior a mixture of earth, fire-shattered stone, and charcoal flecks and nodules.

The three mounds are positioned along the southern bank of a small stream, with two sitting adjacent to one another and a third lying roughly twelve metres to the east. The westernmost is a well-defined horseshoe shape, about 9.7 metres in overall diameter and 1.1 metres high, with its open end facing north-north-east towards the water. Large upright slabs protrude from the base of its southern side. The middle mound is larger, reaching thirteen metres in diameter, though more irregular in outline, with a small flat-topped rise partly blocking its northern opening and two gaps on its southern arc that appear to be of recent, rather than prehistoric, origin. The easternmost mound measures roughly 8.9 metres by 10.5 metres and opens to the north-west. All three lie within a complex of old field walls, suggesting that the landscape around them has been divided and worked across many different periods, layering prehistory beneath later agricultural use. The survey of the Iveragh Peninsula compiled by A. O'Sullivan and J. Sheehan, published by Cork University Press in 1996, recorded this cluster as a notably coherent group within a broader archaeology-rich region.