The size of Cornwallis is approximately 6.8 square kilometres. It has 4 parks covering nearly 1.3% of total area. The population of Cornwallis in 2011 was 224 people. By 2016 the population was 38 showing a population decline of 83.0% in the area during that time. The predominant age group in Cornwallis is 50-59 years. Households in Cornwallis are primarily couples with children and are likely to be repaying not stated per month on mortgage repayments. In general, people in Cornwallis work in a managers occupation. In 2011, 68.8% of the homes in Cornwallis were owner-occupied compared with 72.8% in 2016.