The size of Tonganah is approximately 32.1 square kilometres. It has 4 parks covering nearly 80.1% of total area. The population of Tonganah in 2011 was 296 people. By 2016 the population was 20 showing a population decline of 93.2% in the area during that time. The predominant age group in Tonganah is 60-69 years. Households in Tonganah are primarily couples with children and are likely to be repaying $800 - $999 per month on mortgage repayments. In general, people in Tonganah work in a machinery operators and drivers occupation. In 2006, 39.4% of the homes in Tonganah were owner-occupied compared with 71% in 2011.