In 1977, Columbus and Lake Mills left to join the Capitol Conference and Oregon left to join the Badger Conference. They were replaced by two schools from the Badger Conference (Edgerton and Jefferson) and one from the State Line League (Brodhead). That same year, the Central Suburban Conference changed its name to the Rock Valley Conference, both a reference to the old Rock River Valley League and the revised catchment area. In 1982, Jefferson and Milton both left the Rock Valley to join the Southern Lakes Conference and were replaced by Beloit Catholic (from the IHSA's Trailblazer Conference) and Big Foot (formerly of the Southern Lakes). Palmyra-Eagle joined the conference in 1990 to bring membership up to nine schools. Beloit Catholic left to join the Indian Trails Conference in 1996 for its last few years before it closed in 2000.
2008-present
Membership remained unchanged until 2008 when the conference added four schools. Jefferson made its return from the Southern Lakes Conference, and three newcomers joined: two from the Southern Lakes (East Troy and Whitewater) and one from the Badger Conference (McFarland). The conference also split its membership into North and South Divisions:
North Division
South Division
East Troy
Big Foot
Edgerton
Brodhead
Evansville
Clinton
Jefferson
Palmyra-Eagle
McFarland
Parkview
Whitewater
Turner
This alignment lasted until 2017, when both Palmyra-Eagle and Parkview left the Rock Valley to join more similarly-sized schools in the Trailways Conference. McFarland and Monroe swapped conference affiliations in 2023, with Monroe joining the Rock Valley and McFarland taking their place in the Badger Conference. Delavan-Darien was also welcomed into the Rock Valley from the Southern Lakes Conference that year, and the conference subdivided into the current "Rock" and "Valley" Divisions:
Rock Division
Valley Division
Big Foot
Delavan-Darien
Brodhead
East Troy
Clinton
Jefferson
Edgerton
Monroe
Evansville
Whitewater
Turner
Football-only alignment
In February 2019, in conjunction with the Wisconsin Football Coaches Association, the WIAA released a sweeping football-only realignment for Wisconsin to commence with the 2020 football season and run on a two-year cycle. The Rock Valley Conference entered the 2020 football season with eight members: East Troy, Edgerton, Edgewood, Evansville, Jefferson, McFarland, Monroe and Whitewater. Six members had full affiliation with the Rock Valley Conference with the exception of Edgewood and Monroe, who had primary affiliation with the Badger Conference. In 2022, Edgewood left to join the Capitol Conference as a football-only member with Delavan-Darien moving over from the Southern Lakes Conference as their replacement. Delavan-Darien played as a football-only member in the 2022 season before gaining full affiliation in the Rock Valley Conference the following year. The Rock Valley Conference will maintain its current football alignment until the 2026-2027 realignment cycle. Membership will decrease to seven schools after a complete overhaul, with two schools each joining the Badger Conference (McFarland and Monroe) and Capitol Conference (Edgerton and Jefferson). They will be replaced by full members Big Foot, Clinton and Turner, all making their return from associate membership in the Capitol Conference.
