The size of Dirnbir is approximately 33.9 square kilometres. The population of Dirnbir in 2011 was 324 people. By 2016 the population was 54 showing a population decline of 83.3% in the area during that time. The predominant age group in Dirnbir is 10-19 years. Households in Dirnbir are primarily couples with children and are likely to be repaying under $300 per month on mortgage repayments. In general, people in Dirnbir work in a labourer occupation. In 2006, 55.3% of the homes in Dirnbir were owner-occupied compared with 65.6% in 2011.