Palos Heights, IL has a population of 12,544 and is the 3,299th largest city in the United States. The population density is 3,322 per sq mi which is 1395% higher than the Illinois average and 3567% higher than the national average. The median age in Palos Heights is 53 which is approximately 41% higher than the Illinois average of 37. In Palos Heights, 69% of the population over 15 years of age are married, 86% speak English and 3% speak Spanish. 80% of Palos Heights residents were born in Illinois, 12% were born out of state, 1% were born outside of the United States and 8% were foreign born.