Background: Informed policy and service provision often relies on a sound statistical picture of a population and its geographical dispersion. Such a picture does not presently exist for Indigenous Australians with intellectual disability (ID) and co-occurring challenging behaviour (CB). Method: Population statistics for 18- to 64-year-old Australians were sourced from the 2008 National Aboriginal and Torres Strait Islander Social Survey and 2007-2008 National Health Survey. CB was not directly counted; however, it has been linked to higher severity of intellectual impairment. Results: National prevalence of ID for Indigenous adults was 7.6% and 2.5% for non-Indigenous. ID with profound or severe core activity limitation was 2.1% for Indigenous adults and 0.8% for non-Indigenous. Conclusion: Population statistics afforded a broad picture of ID and severity of intellectual impairment. Policy and service provision for Indigenous peoples will likely benefit from methodologies that supplement population statistics and provide greater understanding of group dispersion.