McLean County is the largest county by land area in the U.S. state of Illinois. According to the 2020 Census, it had a population of 170,954. Its county seat is Bloomington. McLean County is included in the Bloomington–Normal, IL Metropolitan Statistical Area.

Bloomington is a city in and the county seat of McLean County, Illinois, United States. The 2020 census showed the city had a population of 78,680, making it the 13th-most populous city in Illinois and the fifth-most populous outside the Chicago metropolitan area. It is adjacent to the town of Normal, and is the more populous of the two principal municipalities of the Bloomington–Normal metropolitan area, which has a population of roughly 170,000. Bloomington is 135 miles (217 km) southwest of Chicago and 162 miles (261 km) northeast of St. Louis. Bloomington is home to Illinois Wesleyan University and the headquarters for State Farm and Country Financial.