The Manitoba-Dakota League was an independent baseball league based in Manitoba and North Dakota that was founded in 1950. It became the home for many African-American and Latino players. The league lasted through the 1957 season. It was known informally as the Mandak League or Man-Dak League. The league originated as the Manitoba Senior Baseball League founded in 1948, with Jimmy Dunn as its president.

James Archibald Dunn was a Canadian sports executive involved in ice hockey, baseball, fastpitch softball, athletics, football and curling. He was president of the Canadian Amateur Hockey Association (CAHA) from 1955 to 1957, after he served five years as a vice-president. He assumed control of the CAHA when it had lost the confidence of the people to produce a Canada men's national team which would win the Ice Hockey World Championships, and recommended forming a national all-star team based on the nucleus of the reigning Allan Cup champion. He wanted to create more goodwill towards Canada in international hockey, accompanied the Kenora Thistles on an exhibition tour of Japan, then arranged for the Japan men's national team to tour Canada. In junior ice hockey, he was opposed to the mass transfers of players to the stronger teams sponsored by the National Hockey League, and supported weaker provincial champions to have additional players during the Memorial Cup playoffs. After his presidency, he represented the CAHA as a member of the Hockey Hall of Fame selection committee for 15 years.