DemographicsDonnybrook (Qld) is approximately 18.51 square kilometres. In 2016 the population of Donnybrook (Qld) was 617. The population is 54% male and 46% female. On average the monthly mortgage repayments in Donnybrook (Qld) are $1400 to $1799. The most common weekly income bracket is $300 to $399 per week. Weekly rents in the area are on average $275 to $349.