The Giants defeated the Dodgers, six games to three, capturing their second consecutive World's Championship Series.
This was the final season of the NL's Indianapolis Hoosiers & Washington Nationals, and the AA's Kansas City Cowboys.
American Association Opening Day took place on April 17 featuring four teams, while National League Opening Day took place on April 24, featuring all eight teams.
The American Association would see its final day of the regular season on October 15 with four teams playing, while the National League would see its final day of the season on October 5, featuring all eight teams.
The 1889 season saw the following rule changes: An asterisk (*) denotes the ballpark a team played the minority of their home games at Blue laws restricted Sunday activities in several localities, causing several teams of the American Association (which was informally referred to as the "Beer & Whiskey League" due to its openness on alcohol, compared to the National League) to play at ballparks in a different locality.