The size of St Arnaud is approximately 70 square kilometres. It has 7 parks covering nearly 3.9% of total area. The population of St Arnaud in 2011 was 2,618 people. By 2016 the population was 2,178 showing a population decline of 16.8% in the area during that time. The predominant age group in St Arnaud is 60-69 years. Households in St Arnaud are primarily childless couples and are likely to be repaying $1000 - $1399 per month on mortgage repayments. In general, people in St Arnaud work in a labourer occupation. In 2011, 76% of the homes in St Arnaud were owner-occupied compared with 75.8% in 2016. Currently the median sales price of houses in the area is $230,000.