The size of Joanna is approximately 130 square kilometres. It has 5 parks covering nearly 4.6% of total area. The population of Joanna in 2011 was 656 people. By 2016 the population was 92 showing a population decline of 86.0% in the area during that time. The predominant age group in Joanna is 50-59 years. Households in Joanna are primarily childless couples and are likely to be repaying $1400 - $1799 per month on mortgage repayments. In general, people in Joanna work in a managers occupation. In 2011, 74.7% of the homes in Joanna were owner-occupied compared with 64.7% in 2016.