It measures seven metres north to south and barely reaches sixty centimetres in height, and its composition, compacted burnt stone and dark, charred soil beneath a skin of grass, is what gives it away as something far older than the field it occupies.

This is a fulacht fia, a type of prehistoric cooking or processing site found widely across Ireland, typically Bronze Age in date. The characteristic form is the same across thousands of examples: a trough, usually dug near a water source, where stones were heated in a fire and then dropped into water to bring it to a boil. The broken, fire-cracked stones, discarded after use, accumulated over time into exactly the kind of low, horseshoe-shaped mound visible here, open on one side where the trough would have been. At Castleturvin the mound opens eastward, and several large boulders along the north-east edge may simply be natural rock outcrop rather than part of the deposit itself. What makes the site quietly notable is that it does not stand alone. A second fulacht fia lies approximately eighty metres to the south-south-west, suggesting that this particular patch of damp, stream-adjacent ground was returned to repeatedly, perhaps across generations, by people who understood the landscape's usefulness as well as its limitations.