DemographicsDerby (Tas.) is approximately 77.85 square kilometres. In 2016 the population of Derby (Tas.) was 173. The population is 53% male and 47% female. On average the monthly mortgage repayments in Derby (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 $0 to $74.