The region has been occupied by Indigenous Australians for tens of thousands of years, in the west by the Kamilaroi people. In the highlands, the original languages (which are now extinct) included Anaiwan to the south of Guyra and Ngarbal to the north of Guyra. The population of the tablelands has been estimated to be 1,100 to 1,200 at the time of colonisation – quite low in comparison to the Liverpool Plains and Gwyder River region, estimated to be 4,500 to 5,500. Conflict, disease and environmental damage caused the tablelands population to be reduced to 400 by the 1890s.