The size of Nullo Mountain is approximately 339.5 square kilometres. It has 3 parks covering nearly 85.6% of total area. The population of Nullo Mountain in 2011 was 160 people. By 2016 the population was 18 showing a population decline of 88.8% in the area during that time. The predominant age group in Nullo Mountain is 60-69 years. Households in Nullo Mountain are primarily childless couples and are likely to be repaying under $300 per month on mortgage repayments. In general, people in Nullo Mountain work in a managers occupation. In 2006, 14.5% of the homes in Nullo Mountain were owner-occupied compared with 72.6% in 2011.