Despite sporadic archaeological work spanning five decades,the chronology of Aboriginal presence in the mountains of southeast Australia remains poorly understood. Characterised by steep slopes and rugged terrain,this region has possibly always been a marginal area for human habitation,and its occupation chronology can thus play an important role in assessing competing hypotheses regarding past population expansions and cultural responses to environmental change. To improve our understanding of Aboriginal high country chronology,several rockshelters in the Namadgi Ranges in the Australian Capital Territory were excavated. A series of radiocarbon dates from these excavations and a generalised chronostratigraphy of this area are described in this report. Cultural deposits dating to the early to mid-Holocene provide the first substantial evidence that people were active in the high country during the Holocene Optimum (ca 9,000-6,000 years BP). In combination with previously dated Namadgi sites,the new data also confirm an increase in activity at around 2,000 years BP. An apparent decrease in cultural evidence dating to between 4,500 and 2,000 years BP is in contrast to major cultural and population shifts seen in the southeast Australian archaeological record during this time,but whether this reflects an actual behavioural trend or results from external processes affecting cultural deposits is still unclear.