The size of Mannum is approximately 256.3 square kilometres. It has 8 parks covering nearly 0.1% of total area. The population of Mannum in 2011 was 2,567 people. By 2016 the population was 2,651 showing a population growth of 3.3% in the area during that time. The predominant age group in Mannum is 60-69 years. Households in Mannum are primarily childless couples and are likely to be repaying $1000 - $1399 per month on mortgage repayments. In general, people in Mannum work in a trades occupation. In 2011, 70.5% of the homes in Mannum were owner-occupied compared with 68.3% in 2016. Currently the median sales price of houses in the area is $297,500.