what county is bloomington il
About the City. The City of Bloomington is located in the heart of Central Illinois, approximately 125 miles southwest of Chicago, 155 miles northeast of St. Louis, and 64 miles northeast of Springfield, the State Capital. Bloomington is the County Seat of McLean County, the largest county in Illinois (approximately 762,240 acres). Bloomington (pop. 76,610) is a twin City with the Town of Normal (pop. 52,497). Interstates 39, 55 and 74 converge on Bloomington-Normal, as well as US Route 51 and State Route 9.