A flat cemetery, as the name suggests, leaves no mound or monument visible at the surface, which is precisely why such sites so often survive unnoticed until a digger blade catches them.

What came to light was a series of cremation pits, post-holes, and burnt deposits, along with a remarkable quantity of stone finds. In total, 1,229 stone objects were recovered, the vast majority from within the cremation pits themselves. Among them were 1,200 struck and worked flint tools, a category that includes a double-ended scraper, thumbnail and round scrapers, a flint blade, a polished stone axe, and a broken whetstone, as well as sherds of fine prehistoric pottery. Taken together, these objects place the site broadly in the Late Neolithic or Early Bronze Age, a period roughly spanning the centuries around 3000 to 1500 BC. The mix of finds is a curious one: the tools look like the everyday equipment of people who lived and worked here, yet their deliberate placement alongside cremated human remains points strongly toward ritual intent, the two things folded together in a way that makes clean categories difficult. Three distinct areas of burning were identified across the site, though all had been heavily cut about by centuries of agriculture. Stake-holes in the eastern portion may represent the remnants of a fence line, and some pits may originally have served as structural post-holes before being repurposed. The scale of the burial ground begins to make more sense when set against evidence, gathered through related excavation work by Fintan Walsh and colleagues, of a substantial prehistoric settlement spread across the surrounding area, suggesting that Killadreenan was once a place of some significance in this stretch of County Wicklow.