The size of Millie is approximately 330.5 square kilometres. The population of Millie in 2011 was 287 people. By 2016 the population was 22 showing a population decline of 92.3% in the area during that time. The predominant age group in Millie is 10-19 years. Households in Millie are primarily couples with children and are likely to be repaying under $300 per month on mortgage repayments. In general, people in Millie work in a managers occupation. In 2006, 5.8% of the homes in Millie were owner-occupied compared with 32.7% in 2011.