Carol Stream, IL has a population of 40,228 and is the 1,029th largest city in the United States. The population density is 4,403 per sq mi which is 1881% higher than the Illinois average and 4760% higher than the national average. The median age in Carol Stream is 38 which is approximately 1% higher than the Illinois average of 37. In Carol Stream, 58% of the population over 15 years of age are married, 69% speak English and 10% speak Spanish. 64% of Carol Stream residents were born in Illinois, 13% were born out of state, 2% were born outside of the United States and 22% were foreign born.