Anamosa - 2018-19 thru PRESENT
Bellevue - 2013-14 thru PRESENT
Camanche - 2013-14 thru PRESENT
Cascade - 2013-14 thru PRESENT
Monticello - 2013-14 thru PRESENT
North Cedar - 2008-09 thru PRESENT
Northeast - 2013-14 thru PRESENT
Durant - 2008-09 thru PRESENT
Iowa City Regina - 2008-09 thru PRESENT
Mid-Prairie - 2008-09 thru PRESENT
Tipton - 2008-09 thru PRESENT
Wilton - 2008-09 thru PRESENT
West Branch - 2008-09 thru PRESENT
West Liberty - 2008-09 thru PRESENT
Anamosa joins from the WaMac Conference. Membership increases to 14.
Bellevue, Camanche, and Northeast join from the disbanding Big East Conference. Cascade and Monticello join from the Tri-Rivers Conference. Membership increases to 13. Conference renamed River Valley Conference.
Durant, Mid-Prairie, Regina, Tipton, West Branch, West Liberty, and Wilton of the disbanding Eastern Iowa Hawkeye Conference; and North Cedar of the Big East Conference form the Cedar Valley Conference. Original membership is 8.
Andrew - 1993-94 thru 2010-11
Bellevue - 1993-94 thru 2012-13
Bennett - 1993-94 thru 2004-05
Calamus-Wheatland - 1993-94 thru 2012-13
Camanche - 2003-04 thru 2012-13
Clinton Mater Dei - 1993-94 thru 2012-13
East Central - 1993-94 thru 2010-11
Lisbon - 1993-94 thru 2012-13
Marquette Catholic, Bellevue - 1993-94 thru 2012-13
Midland - 1993-94 thru 2012-13
North Cedar - 1993-94 thru 2007-08
Northeast - 1993-94 thru 2012-13
Olin - 1993-94 thru 2010-11
Preston - 1993-94 thru 2012-13
Marquette Catholic, Bellevue, Lisbon, Midland, Calamus-Wheatland, Prince of Peace Prep, and a reorganized Easton Valley (made up of Preston and defunct East Central) leave for the Tri-Rivers Conference. Bellevue, Northeast, and Camanche leave for the Cedar Valley Conference, which forms the River Valley Conference. The conference disbands.
Andrew, Olin, and East Central close. Membership decreases to 9.
North Cedar leaves to help form the Cedar Valley Conference. Membership decreases to 12.
Bennett is absorbed by Durant (Eastern Iowa Hawkeye Conference). Membership decreases to 13.
Camanche joins from the disbanding Big Bend Conference. Membership increases to 14.
Mater Dei changes it name to Prince of Peace Prep. Membership remains at 13.
The Wapsie Conference (made up of Marquette Catholic, Bellevue, Calamus-Wheatland, Bellevue, Andrew, Bennett, and Mater Dei) merges with the Mid-East Conference (made up of Northeast, Midland, Lisbon, Preston, Olin, East Central, Clarence-Lowden, and Lincoln, Stanwood) to form the Big East Conference. Clarence-Lowden and Lincoln, Stanwood consolidate to form North Cedar and remain in the new league. Original membership is 13.
Anamosa - 1987-88 thru 2002-03
Camanche - 1987-88 thru 2002-03
Cascade - 1987-88 thru 2002-03
Central Clinton of DeWitt - 1987-88 thru 2002-03
Dyersville Beckman - 1987-88 thru 2002-03
Maquoketa - 1987-88 thru 2002-03
Monticello - 1987-88 thru 2002-03
Western Dubuque -1987-88 thru 2002-03
Beckman, Western Dubuque, and Central Clinton join the WaMaC Conference. Monticello, Anamosa, and Cascade join the Tri-Rivers Conference. Camanche joins the Big East Conference. The league disbands.
Maquoketa leaves for the WaMaC Conference. Membership decreases to 7.
Maquoketa, Monticello, and Anamosa of the WaMaC Conference; Beckman, Western Dubuque, Central Clinton, Camanche, and Cascade, all previously independent, re-establish the Big Bend Conference. Membership is 8.
Bellevue - 1978-79 thru 1982-83
Camanche - 1975-76 thru 1984-85
Central Clinton/Dewitt - 1975-76 thru 1984-85
Clinton Saint Mary's - 1975-76 thru 1979-80
Clinton Mater Dai - 1980-81 thru 1983-84
Northeast - 1975-76 thru 1983-84
North Scott - 1975-76 thru 1977-78
Pleasant Valley - 1975-76 thru 1984-85
Western Dubuque -1976-77 thru 1984-85;
The league disbands. Pleasant Valley, Central Clinton, Cascade, Western Dubuque, and Camanche become independents.
Mater Dei (to Wapsie Conference) and Northeast (to Mid-East Conference) leave the conference. Membership decreases to 5.
Bellevue leaves the conference for Wapsie Conference. Membership decreases to 7.
St. Mary's, Clinton becomes Mater Dei. Membership remains at 8.
Cascade joins from the Eastern Iowa Conference. Bellevue joins from the Great River Conference. North Scott leaves to help found the Mississippi Athletic Conference. Membership increases to 8.
Western Dubuque joins from the Eastern Iowa Conference. Membership increases to 7.
Central Clinton, North Scott, and St. Mary's, Clinton of the disbanding Illiowa Conference; and Camanche, Northeast, and Pleasant Valley of the disbanding Bi-State Conference form the Big Bend Conference. Original membership is 6.
Camanche - 1970-71 thru 1974-75
Northeast - 1970-71 thru 1974-75
Pleasant Valley - 1970-71 thru 1974-75
Erie (IL) - 1970-71 thru 1974-75
Prophetstown (IL) - 1970-71 thru 1974-75
Pleasant Valley, Camanche, and Northeast leave to help found the Big Bend Conference. Erie (IL) and Prophetstown (IL) leave to helpfound the Three Rivers Conference. Conference disbands.
Pleasant Valley, Camanche, Northeast, Erie (IL), and Prophetstown (IL) form the Bi-State Conference. Original membership is 5.