The site is a fulacht fia, a type of monument found in enormous numbers across Ireland, typically dating to the Bronze Age. The basic principle is straightforward: a trough, usually timber-lined, was filled with water, and stones heated in a nearby fire were dropped in to bring it to a boil. The shattered, heat-cracked stones were discarded in a horseshoe-shaped mound around the trough, and it is these mounds, dark and waterlogged, that survive in the landscape today.

At Tooreen, the site sits in boggy ground to the south-east of a drain, and it was the cutting of that drain which offered a glimpse into what lies beneath: burnt material was observed in the exposed section of earth, the telltale dark, charcoal-flecked deposit that archaeologists associate with fulacht fia activity. It is a modest piece of evidence, but a telling one. Boggy, low-lying ground is precisely where these sites tend to cluster, partly because such locations offered a reliable water source and partly because the anaerobic conditions of a wetland preserve organic material that would otherwise vanish entirely. The burnt stone and charred debris at Tooreen are likely the accumulated waste of repeated use, perhaps over generations.