The Interstate Eight Conference (Interstate 8 or I–8) is an athletic conference of Illinois high schools that are members of the Illinois High School Association (IHSA). The conference currently has six member schools throughout Northern Illinois that compete in 12 different sports (boys' basketball, girls' basketball, girls' volleyball, boys' golf, girls' golf, football, boys' soccer, girls' soccer, wrestling, baseball, softball, cross country, and track and field). The Interstate Eight began in 1979 and originally had eight schools—Coal City, Dwight, Marseilles, Plano, Reed-Custer, Seneca, Wilmington, and Yorkville. Sandwich soon entered the I-8 when Marseilles dropped out. In 1991, Yorkville was replaced by Lisle. In 2006 Herscher, Manteno, Peotone, and Westmont joined the conference. Despite the conference growing from eight to 12 teams, the conference name remained Interstate 8. Dwight left the conference prior to the 2014–15 season while Streator joined the conference. In 2019–20, Reed-Custer, Manteno, Peotone, Herscher, Wilmington, Seneca, Streator, Coal City, Westmont and Lisle left the conference leaving only Plano and Sandwich in the conference. That year, the conference added six schools from the soon to be defunct Northern Illinois Big 12 Conference. These included Kaneland, LaSalle-Peru, Morris, Ottawa, Rochelle, and Sycamore. These moves left Plano as the only remaining founding member of the conference. In 2022, Sandwich High School and Plano High School announcing to leave the conference to join Kishwaukee River Conference starting in 2023–24 season. Plano was the final remaining original I8C member, completing nearly 45 seasons. This left the Interstate Eight with, ironically, only six schools. All of which are the former NI-Big 12 schools. Most of the member schools are/were in rural/smaller towns. Former members Westmont and Lisle are suburbs of Chicago but enrollments are small in size. Westmont's population is divided between the varying schools in the area, including high schools in Darien, Woodridge, Hinsdale, Bolingbrook, Naperville, Lisle, Lombard, and Glen Ellyn. Lisle's enrollment is small, due to Lisle's relatively small size as a city, as well as being located east of Naperville, which has at least four high schools in the immediate vicinity, as well as the Glenbard schools and Wheaton-Warrenville South all being within a close proximity to the high school. The Conference is divided into Large and Small divisions during football season and teams only play members of their division for the conference schedule. Baseball and softball are also divided into North and South divisions. In all other sports, the conference is undivided.

Members

There are six current members of the conference

Current Members

Former Members

Membership Timeline

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State titles

Football

Football is based on an 8 class system since 2001.

Boys baseball

Wrestling

Boys basketball

Boys golf

Boys soccer

Girls soccer

Competitive cheerleading

Competitive Dance Team

Boys cross country

Cross Country is based on a 3 class system since 2007.

Girls cross country

Cross Country is based on a 3 class system since 2007.

Girls track and field

Girls softball

Girls volleyball

Scholastic Bowl

Lisle (2011, 2012, 2013, 2014, 2015, 2016 wins)