1970: Regina Pats are granted a franchise, and play in the Eastern Division; Medicine Hat Tigers are granted a franchise, and play in the Western Division.
1971: Estevan Bruins move to New Westminster, and play in the Western Division. Victoria Cougars, and Vancouver Nats granted franchises, both play in the Western Division. Swift Current and Saskatoon move to the Eastern Division.
1976: League splits into three divisions: East (Brandon, Saskatoon, Flin Flon, Regina); Central (Medicine Hat, Winnipeg, Lethbridge, Calgary); West (New Westminster, Kamloops, Portland, Victoria). Edmonton Oil Kings move to Portland. Winnipeg Clubs become Winnipeg Monarchs.
1977: Winnipeg Monarchs and Kamloops Chiefs fold. Billings Bighorns are granted a franchise and play in the Central Division. Seattle Breakers granted a franchise and play in the Western Division. Calgary Centennials become the Calgary Wranglers.
1978: The WCHL becomes the Western Hockey League. Flin Flon Bombers move to Edmonton.
1979: The WHL splits into two divisions: West (Portland, Victoria, Seattle, New Westminster) and East (Regina, Calgary, Medicine Hat, Billings, Brandon, Lethbridge, Saskatoon, Great Falls) Edmonton Oil Kings move to Great Falls. Great Falls Americans fold on December 16.
1980: Winnipeg Warriors granted a franchise and play in the East Division. Spokane Flyers granted a franchise and play in the West Division.
1982: Billings Bighorns fold. Prince Albert Raiders, Nanaimo Islanders, and Kelowna Wings are all granted franchises. Prince Albert plays in the East Division, Kelowna and Nanaimo in the West.
1995: WHL divides into three divisions: West (Spokane, Tri-Cities, Tacoma, Seattle, Kamloops, Portland, Prince George), Central (Swift Current, Lethbridge, Medicine Hat, Red Deer, Calgary), and East (Brandon, Prince Albert, Regina, Saskatoon, Moose Jaw). Calgary Hitmen are granted a franchise. Tacoma Rockets move to Kelowna.
1996: Edmonton Ice are granted a franchise, and play in the central division. Swift Current moves to the east division.
2001: WHL divides into two conferences of two divisions each: Eastern Conference: East Division (Brandon, Regina, Moose Jaw, Saskatoon, Prince Albert); Central Division (Red Deer, Swift Current, Lethbridge, Calgary, Medicine Hat); Western Conference: British Columbia Division (Kamloops, Kootenay, Prince George, Kelowna, Vancouver); United States Division (Portland, Spokane, Tri-Cities, Seattle). Vancouver Giants granted a franchise.
2003: Everett Silvertips are granted a franchise and play in the United States division.
2005: Tri-Cities Americans' plan to move to Chilliwack is voted down by the league board of governors