Arlington Heights is a village in Cook and Lake counties in the U.S. state of Illinois. An affluent suburb of Chicago, it lies about 25 miles northwest of the city's downtown. The population was 76,031 at the 2000 census. Arlington Heights is known for Arlington Park Race Track, home of the Arlington Million, a Breeders' Cup qualifying event; also hosted the Breeders' Cup Classic in 2002. It is also home to the Arlington Heights Memorial Library, which has one of the largest collections in the state, as well as the Metropolis Performing Arts Centre, Saint Viator High School, John Hersey High School, South Middle School and Thomas Middle School.