1967-68: Center Point, Springville, North-Linn, and Central City leave to help form the Tri-Rivers Conference. Linn-Mar leaves to help form the East Central Conference. Lincoln, Stanwood, Midland, Olin become independents.

1966-67: Springville joins. Coggon consolidates with non-football schools to form North-Linn. The new school remains in the conference. Membership increases to 8.

1965-66: Center Point joins. Membership increases to 7.

1964-65: Coggon, Lincoln, Stanwood, Linn-Mar, Midland, Olin, and Central City form the Pinicon Conference. Membership is 6.