Derryvree Ice-Free Interval
Archived: 8 September 2026
Around 31,976 BCE, Ireland had no securely attested human population, settlement or political history. Evidence from Derryvree, County Fermanagh, places the island within a later Marine Isotope Stage 3 ice-free interval, before major expansion of the last Irish Ice Sheet. Freshwater sediments, dated broadly to 36,900–31,700 years before present, indicate cold periglacial conditions and open tundra vegetation of herbs, grasses, sedges and mosses. Fossil records suggest shifting cold-adapted mammal communities, but cannot establish species present locally in that year. Approaching glaciation subsequently reshaped Ireland’s landforms and obscured much earlier evidence. The earliest persuasive human visit occurred over twenty millennia later.