Baseball teams established in 1977

The Toronto Blue Jays are a Canadian professional baseball team based in Toronto. The Blue Jays compete in Major League Baseball (MLB) as a member club of the American League (AL) East Division. Since 1989, the team has played its home games primarily at Rogers Centre in downtown Toronto.

The Seattle Mariners are an American professional baseball team based in Seattle. The Mariners compete in Major League Baseball (MLB) as a member club of the American League (AL) West Division. The team joined the American League as an expansion team in 1977, originally playing their home games in the Kingdome. Since July 1999, the Mariners' home ballpark has been T-Mobile Park, located in the SoDo neighborhood of Seattle.

Minor League Baseball Class AAA franchise in Columbus, Ohio, USA