Bloomington-Normal refers to the twin municipalities of Bloomington and Normal in McLean County, in Central Illinois. Bloomington is a city in McLean County, Illinois, United States and the County seat. Normal is an Incorporated town in McLean County, Illinois, United States. McLean County is the largest County in the US state of Illinois. Central Illinois is a region of the US state of Illinois that consists of the entire central section of the state divided in thirds from north to south The combined population of the two communities in a special census in 2006 was 125,000.