The size of Collie is approximately 53.4 square kilometres. It has 33 parks covering nearly 25.2% of total area. The population of Collie in 2011 was 7,962 people. By 2016 the population was 7,578 showing a population decline of 4.8% in the area during that time. The predominant age group in Collie is 60-69 years. Households in Collie are primarily childless couples and are likely to be repaying $1000 - $1399 per month on mortgage repayments. In general, people in Collie work in a trades occupation. In 2011, 73.4% of the homes in Collie were owner-occupied compared with 71.8% in 2016. Currently the median sales price of houses in the area is $216,000.