At that time, the existing Big Twelve Conference membership of Bloomington, Champaign Central, Danville, Stephen Decatur, Lincoln, Mattoon, Springfield & Urbana voted to drop Springfield and add existing Capitol Conference members Champaign Centennial, Decatur Eisenhower, Decatur MacArthur & Normal Community, as well as Rantoul.
[1] Jacksonville joined the short-lived Greater Midwestern Conference (along with Chatham Glenwood, Hannibal (Missouri), Macomb & Quincy Notre Dame) for five years, then become an independent.
[2] With these five schools desiring to re-establish local rivalries and reduce travel expenses, the Central State Eight Conference came to fruition.
[9] Quincy Notre Dame is expected to join the conference in 2024 for football only.
The conference is centered on high schools in the Springfield/Sangamon County (Illinois) area.