Darien, IL has a population of 22,232 and is the 1,959th largest city in the United States. The population density is 3,589 per sq mi which is 1514% higher than the Illinois average and 3861% higher than the national average. The median age in Darien is 46 which is approximately 23% higher than the Illinois average of 37. In Darien, 64% of the population over 15 years of age are married, 77% speak English and 4% speak Spanish. 70% of Darien residents were born in Illinois, 10% were born out of state, 2% were born outside of the United States and 18% were foreign born.