DemographicsCastle Doyle is approximately 90.98 square kilometres. In 2016 the population of Castle Doyle was 164. The population is 54% male and 46% female. On average the monthly mortgage repayments in Castle Doyle are $1000 to $1399. The most common weekly income bracket is $2000 to $2999 per week. Weekly rents in the area are on average $0 to $74.