In 1968, the St. Thomas Barons, Sarnia Legionnaires, Guelph Imperials, Chatham Maroons and Brantford Foresters broke away from the Ontario Hockey Association to form a Junior "A" League known as the Western Ontario Junior A Hockey League.
A year later, the OHA pulled together a bunch of local teams (the Waterloo Siskins, Stratford Warriors, Sarnia Bees, St.Marys Lincolns and the London Squires) as well as the return of the Strathroy Rockets (who had joined the Central Junior B league for a season) and formed a new Western Ontario Junior "B" Hockey League.
According to the WOJHL history, a re-organization of Ontario's Jr. B hockey teams occurred prior to the 1978/79 with the folding of the short lived Southwestern Junior B Hockey League and the Mid-Ontario Junior B Hockey League.
The realignment meant that the OHA had consolidated the Southern Ontario region from 7 to 5 Junior "B" leagues.
In 1993, the Central league was promoted to Tier II Junior "A" as well.