After 1970, the TBJHL was relegated to Tier II Junior A and competed for the Manitoba Centennial Trophy until the league folded in 1980.
Due to its location, the Thunder Bay league often switched from East to West year-to-year in National playdowns.
Thunder Bay Junior A Hockey League teams made the Memorial Cup finals four times in fifty years, winning Canada's top junior hockey prize in 1922 (Fort William War Veterans) and 1948 (Port Arthur West End Bruins).
To get there, the Vets had to defeat Toronto Aura Lee in the Eastern Canada final, beating them 5–3 in a one-game showdown.
In 1947–48, the Port Arthur West End Bruins finished the regular season in first place with a record of 9 wins, no losses, no ties.
In the Eastern Canadian semi-final, the Bruins had to play the Manitoba Junior Hockey League's Winnipeg Monarchs.
Next, Port Arthur found themselves in the Abbott Cup final against the Southern Alberta Junior Hockey League's Lethbridge Native Sons.
Lethbridge put the series on the brink with a 5–4 win before Port Arthur came back with three solid victories; 5–0, 6–4, 11–1; to come from behind and take the Abbott Cup.
From the 1964 until 1969, the TBJHL had a rivalry and was in direct competition annually for the TBAHA seed to the Memorial Cup against the neighbouring Northwestern Ontario Junior Hockey League.
To balance the power a bit, the CAHA assigned the TBJHL to the Eastern section of the national playdowns for the first time since 1927.
For the 1972–73 season, the newly formed Can-Am Junior Hockey League was actually allowed to represent the Thunder Bay district at the National level.
The 1978–79 season began with the merging of the Beavers, Canadians, and Hurricanes into the Degagne Buccaneers and Case Eagles and Blades into the Thunder Bay North Stars.
Both the North Stars and Buccaneers went out of business on July 6, 1980, when the TBAHA revoked their Junior A status in favour of what would be the Kings.
The winner of the TBJHL Playoffs was awarded the Jack Adams Trophy as Thunder Bay Amateur Hockey Association Junior "A" Champions.
Instead of continuing with the slowly faltering league, the Thunder Bay Amateur Hockey Association decided it would more efficient to form a Citywide superleague with one top-level team from each major level.
By 1982 the Blazers merged with the Twins as the Intermediate level was ended by the Canadian Amateur Hockey Association, the Twins moved to the Central Senior Amateur Hockey League in Manitoba, and the Nor'Westers moved into the Ontario University Association.