The size of Castle Hill is approximately 18.9 square kilometres. It has 44 parks covering nearly 9.6% of total area. The population of Castle Hill in 2011 was 37,916 people. By 2016 the population was 39,624 showing a population growth of 4.5% in the area during that time. The predominant age group in Castle Hill is 40-49 years. Households in Castle Hill are primarily couples with children and are likely to be repaying $3000 - $3999 per month on mortgage repayments. In general, people in Castle Hill work in a professional occupation. In 2011, 79% of the homes in Castle Hill were owner-occupied compared with 74.5% in 2016. Currently the median sales price of houses in the area is $2,000,000.