Bourbonnais, IL has a population of 18,607 and is the 2,345th largest city in the United States. The population density is 1,965 per sq mi which is 784% higher than the Illinois average and 2069% higher than the national average. The median age in Bourbonnais is 33 which is approximately 11% lower than the Illinois average of 37. In Bourbonnais, 52% of the population over 15 years of age are married, 94% speak English and 4% speak Spanish. 77% of Bourbonnais residents were born in Illinois, 20% were born out of state, 0% were born outside of the United States and 3% were foreign born.