[1] Four long-time independents (Eau Claire, La Crosse Central, Marinette and Menominee (MI)) joined with Wausau, who was forced out of the Wisconsin Valley Conference.
[2][3] The twin cities of Marinette and Menominee left the conference in 1963, primarily due to travel issues and lack of competitiveness in basketball.
[4] The two exiting schools were replaced by four newcomers: Chippewa Falls from the disbanded Mississippi Valley Conference, the newly opened Eau Claire North, and two former independents in La Crosse Logan and Menomonie.
[6] The two Wausau high schools would go back to the Wisconsin Valley Conference in 1973,[7][8] and membership stayed consistent until realignment in the late 1980s.
New Richmond briefly joined the Big Rivers in 1998 from the Middle Border Conference,[12] which they returned to after a four-year stint.