At the 2011 census, there were 15,791 people in the Muswellbrook Shire local government area, of these 51.7 per cent were male and 48.3 per cent were female. Aboriginal and Torres Strait Islander people made up 5.4 per cent of the population, which was significantly higher than the national and state averages of 2.5 per cent. The median age of people in the Muswellbrook Shire was 34 years, which was lower than the national median of 37 years. Children aged 0 – 14 years made up 22.8 per cent of the population and people aged 65 years and over made up 10.6 per cent of the population. Of people in the area aged 15 years and over, 47.0 per cent were married and 11.8 per cent were either divorced or separated.

Population growth in the Muswellbrook Shire between the 2001 census and the 2006 census was 3.25 per cent; and in the subsequent five years to the 2011 census, population growth was 3.64 per cent. When compared with total population growth of Australia for the same periods, being 5.78 per cent and 8.32 per cent respectively, population growth in the Muswellbrook Shire local government area was approximately half the national average. The median weekly income for residents within the Muswellbrook Shire was marginally higher than the national average.

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