The conference was founded in 2014 with the following charter members:
Charlotte,
Coldwater,
Harper Creek,
Jackson Lumen Christi,
Jackson Northwest,
Marshall,
Parma Western, and
Pennfield. After the 2015-16 school year, Charlotte left the conference and eventually rejoin the
Capital Area Activities Conference.
Hastings from the
Ottawa-Kent Conference was selected to replace Charlotte starting in the 2016-17 school year. In August 2022, it was announced that Lumen Christi, the smallest member and the only private school in the conference would depart the Interstate 8 to join the
Catholic High School League beginning in the 2023-24 school year. With Lumen Christi's departure, the remaining seven schools at some point or another participated in the old Twin Valley Conference that existed from 1931 to 2001. In February 2026, it was announced that Northwest, the largest member in the conference would depart the Interstate 8 to join the
Southeastern Conference (MHSAA) in the 2027-2028 school year. ==Member schools==