Bloomington is a city in McLean County, Illinois, United States, and its county seat. 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.