Kildeer, IL has a population of 3,976 and is the 7,477th largest city in the United States. The population density is 939 per sq mi which is 322% higher than the Illinois average and 936% higher than the national average. The median age in Kildeer is 44 which is approximately 19% higher than the Illinois average of 37. In Kildeer, 73% of the population over 15 years of age are married, 85% speak English and 2% speak Spanish. 59% of Kildeer residents were born in Illinois, 28% were born out of state, 1% were born outside of the United States and 12% were foreign born.