as of the 2016 census, 2,193 people resided in st arnaud. the median age of persons in st arnaud was 52 years. children aged 0-14 years made up 13.7% of the population. people over the age of 65 years made up 30.8% of the population there were slightly more females than males with 52.1% of the population female and 47.9% male. the average household size is 2 people per household. the average number of children per family for families with children is 1.8.