Formed in 1967, the conference has enjoyed long-term stability while enduring periods of significant change over its 50-plus year history.
[2] High schools competing throughout most of the 1930s, 40s and 50s included Alburnett, Center Point, Central City, Coggon, Ely, Lisbon, Mt.Vernon, Palo, Springville, Toddville, Troy Mills, Viola and Walker.
In January 1951, 8 schools, Alburnett, Center Point, Central City, Palo, Toddville, Troy Mills, Viola and Walker, joined together to form what was tentatively named the Upper Linn basketball league.
Coggon and Springville attended the meeting but decided not to join, while Lisbon was already affiliated with the Wapsi-Eight league, Mt.
Coggon, Troy Mills and Walker remained a part of the league, but were playing their first year of competition as North Linn.
[15] The combined effect was a net loss of 3 teams, leading the All-Ac to reconfigure and reemerge the following season as the Tri-Rivers Conference.
East Buchanan (Winthrop) returned to join its former All-Ac competitors following a 5-year hiatus in the Upper Mississippi League.
In 2003–04, the Tri-Rivers expanded to 12 with the addition of Anamosa, Cascade, and Monticello from a struggling Big Bend Conference.
[20] At that point the conference was split into two divisions: River (larger schools) Anamosa, Cascade, CPU, Maquoketa Valley, Monticello and Starmont, and Valley (smaller schools) Alburnett, Central City, East Buchanan, Edgewood–Colesburg, North Linn and Springville.
The order moved Cascade and Monticello from the Tri-Rivers to the newly formed River Valley Conference.
Coming from the disbanded Big East were Bellevue Marquette, Calamus–Wheatland, Clinton Prince of Peace, Easton Valley (Preston), Lisbon and Midland (Wyoming).
A 6'6" power forward, he averaged 16.9 points a game in college, and was a first-round pick of the 1974 NBA draft by the Detroit Pistons.