Chicago, IL has a population of 2,714,017 and is the 3rd largest city in the United States. The population density is 11,938 per sq mi which is 5270% higher than the Illinois average and 13077% higher than the national average. The median age in Chicago is 34 which is approximately 9% lower than the Illinois average of 37. In Chicago, 41% of the population over 15 years of age are married, 64% speak English and 25% speak Spanish. 59% of Chicago residents were born in Illinois, 18% were born out of state, 2% were born outside of the United States and 21% were foreign born.