DemographicsNullamanna is approximately 263.61 square kilometres. In 2016 the population of Nullamanna was 158. The population is 57% male and 43% female. On average the monthly mortgage repayments in Nullamanna are $600 to $799. The most common weekly income bracket is $300 to $399 per week. Weekly rents in the area are on average $0 to $74.