DemographicsWallumbilla is approximately 93.95 square kilometres. In 2016 the population of Wallumbilla was 388. The population is 54% male and 46% female. On average the monthly mortgage repayments in Wallumbilla are $1000 to $1399. The most common weekly income bracket is $300 to $399 per week. Weekly rents in the area are on average $0 to $74.