Australians are a very mobile population, showing high levels of permanent movement and nonpermanent circulation within Australia and an increasing level of emigration. This article describes some of the major patterns of Australian internal migration and examines the factors shaping them and the emerging social, economic, political and environmental implications of Australian population mobility. Internal migration, combined with international immigration settlement patterns, is the major cause of regional variations in population growth rate. Some States have developed population policies that seek to influence internal migration trends, e. g. by increasing regional settlement. In non-metropolitan Australia, there is increasing polarisation between growing coastal, near metropolitan or other amenity-rich areas, the so-called 'sea change', 'hill change' or 'tree change' phenomena, and the more remote wheat-pastoral zones. The study reviews research into the strong and complex, but as yet poorly-understood, influence of population mobility on the spatial distribution of poverty.