Preston Heights, IL has a population of 2,916 and is the 8,949th largest city in the United States. The population density is 3,396 per sq mi which is 1428% higher than the Illinois average and 3649% higher than the national average. The median age in Preston Heights is 41 which is approximately 9% higher than the Illinois average of 37. In Preston Heights, 44% of the population over 15 years of age are married, 78% speak English and 21% speak Spanish. 66% of Preston Heights residents were born in Illinois, 21% were born out of state, 1% were born outside of the United States and 13% were foreign born.