Rantoul, IL has a population of 13,238 and is the 3,153rd largest city in the United States. The population density is 1,559 per sq mi which is 601% higher than the Illinois average and 1621% higher than the national average. The median age in Rantoul is 32 which is approximately 15% lower than the Illinois average of 37. In Rantoul, 52% of the population over 15 years of age are married, 89% speak English and 9% speak Spanish. 66% of Rantoul residents were born in Illinois, 26% were born out of state, 2% were born outside of the United States and 6% were foreign born.