DemographicsGilgai is approximately 86.17 square kilometres. In 2016 the population of Gilgai was 720. The population is 50% male and 50% female. On average the monthly mortgage repayments in Gilgai 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.