Bolingbrook, IL has a population of 74,320 and is the 480th largest city in the United States. The population density is 3,016 per sq mi which is 1257% higher than the Illinois average and 3229% higher than the national average. The median age in Bolingbrook is 35 which is approximately 7% lower than the Illinois average of 37. In Bolingbrook, 60% of the population over 15 years of age are married, 67% speak English and 19% speak Spanish. 63% of Bolingbrook residents were born in Illinois, 14% were born out of state, 1% were born outside of the United States and 22% were foreign born.