This is a fulacht fia, a type of monument found across Ireland in which water was heated by dropping fire-cracked stones into a trough, allowing meat or other foodstuffs to be cooked. The heat-shattered stones were then discarded, building up over time into the characteristic horseshoe-shaped mounds that survive across the Irish landscape today.

This particular site, near Islands in County Kilkenny, was uncovered in 2006 during excavations carried out ahead of the M8/N8 Cullahill to Cashel Road Improvement Scheme. The mound itself measured 12.5 metres long, 10 metres wide, and just 0.16 metres deep, composed of sandy silt packed with charcoal and heat-shattered stone. Beneath it, excavators found a rectangular trough and two pits. A radiocarbon date taken from the trough placed its use between approximately 1740 and 1520 cal BC, placing it firmly in the Middle Bronze Age. Notably, a second fulacht fia was identified around 20 metres to the east, suggesting this stretch of wetland edge was a place people returned to repeatedly, perhaps drawn by reliable access to water from the river close by.