Australia’s Eastern Highlands have traditionally been viewed as a cold-climate barrier to Late Pleistocene mobility, with older evidence restricted to elevations below the periglacial zone. However, this model has not been adequately tested with regionally specific, high-resolution archaeological data. Here we report new excavation results from a high-altitude (1,073m) cave, Dargan Shelter, in the upper Blue Mountains, which indicate that occupation first occurred ~ 20,000 years ago, during the last glacial maximum (LGM), making this the highest elevation Pleistocene site so far identified in Australia. We provide evidence for previously undetected interactions along the mountain range and the repeated use of this cold-climate landscape during the Late Pleistocene. Our results align the Australian continent for the first time with global sequences which indicate that cold climates were not necessarily natural barriers to human mobility and occupation.