DemographicsMiddleton (Tas.) is approximately 15.85 square kilometres. In 2016 the population of Middleton (Tas.) was 252. The population is 50% male and 50% female. On average the monthly mortgage repayments in Middleton (Tas.) are $1000 to $1399. The most common weekly income bracket is $300 to $399 per week. Weekly rents in the area are on average $275 to $349.