Kankakee, IL has a population of 26,424 and is the 1,628th largest city in the United States. The population density is 1,761 per sq mi which is 692% higher than the Illinois average and 1843% higher than the national average. The median age in Kankakee is 34 which is approximately 8% lower than the Illinois average of 37. In Kankakee, 42% of the population over 15 years of age are married, 83% speak English and 16% speak Spanish. 71% of Kankakee residents were born in Illinois, 18% were born out of state, 0% were born outside of the United States and 10% were foreign born.