The IBL was founded in 1919 with just four teams—Galt, Guelph, Stratford and Kitchener—and is believed to be the oldest amateur men's league in Canada and also one of the best, regarding quality of play. During the early years, the league expanded to include the cities of London, Brantford, Preston and St. Thomas, Ontario.
It was previously known as the Intercounty Major Baseball League and the Senior Intercounty Baseball League. The teams play for the Jack and Lynne Dominico Trophy, which is awarded to the league champions. Jack and (and the late Lynne) Dominico own the Toronto Maple Leafs Baseball Club.
The is the only Amateur that I will cover
1919 Galt, Guelph, Stratford and Kitchener
1920 to 1924 Unknown Teams
1925 Brantford, Galt, Guelph, London, Preston, Stratford, St Thomas
1926 to 1933
1934 Brantford, Guelph, Kitchener, London, Stratford, Kitchener
1935 to 1945 Unknown Teams
1946 Galt, Guelph, Kitchener, London, Stratford, Waterloo
1947 Brantford and Hamilton enter the League
1948 Hamilton has left the League
1949 St Thomas has enter the League
1950 to 1951 No Teams enter or left the league
1952 Stratford has left the League
1953 Oshawa and St Thomas has enter the League
1954 Oshawa has left the league and Waterloo . During the Season Guelph move to Waterloo.
1955 Oshawa has enter the League and Waterloo has left the League
1956 Galt has left the League
1957 Galt, Guelph, Oakville and Listowel has enter the League and London has left the League
1958 Hamilton and London has enter the League.
1959 to 1961 No Teams enter or left the league
1962 Hamilton, Listowel and St Thomas has left the League
1963 No Teams enter or left the league
1964 Stratford has enter the League
1965 Listowel has enter the League
1966 Hamilton has enter the Legue
1967 to 1968 Unknown Teams
1969 Galt, Guelph, Hamilton, Kitchener, Listowel, London, Stratford and Toronto
1970 to 2000 Unknown Teams
2001 Barrie, Brantofrd, Guelph, Hamilton, Kitchener, London, St Thomas, Toronto, Waterloo
2002 Oshawa enter the league
2003 Stratford enter the league and St Thomas and Waterloo has left the league
2005 to 2008 No Teams enter or left the league
2010 Barrie, Brantford, Guelph, Hamilton, Kitchener, London, Mississauga, Ottawa, Toronto
2011 Burlington enter the league and Guelph and Mississauga left the league
2012 Guelph enter the league.
2013 Ottawa has left the league.
2014 No Teams enter or left the league
2015 No Teams enter or left the league
2016 No Teams enter or left the league
2017 No Teams enter or left the league