DemographicsLower Marshes is approximately 75.48 square kilometres. In 2016 the population of Lower Marshes was 9. The population is 67% male and 33% female. On average the monthly mortgage repayments in Lower Marshes are $0 to $299. The most common weekly income bracket is $800 to $999 per week. Weekly rents in the area are on average $0 to $74.