The 1885 major league baseball season began on April 18, 1885. The regular season ended on October 15, with the Chicago White Stockings and the St. Louis Browns as regular season champions of the National League and American Association, respectively. The postseason began with Game 1 of the second World's Championship Series on October 14 and ended with Game 7 on October 24, in what was a best-of-seven-playoff. The White Stockings and Browns ended the series in a disputed tie in seven games. This dispute was due to the Browns not considering their forfeit in Game 2 as a voided game, and as a result, claimed victory.
Prior to the 1885 season, the unstable single season Union Association disbanded. The St. Louis Maroons of the Union Association joined the National League, in place of the disbanding Cleveland Blues. The twelve-team American Association would contract down to eight teams, with the Columbus Buckeyes, Indianapolis Hoosiers, and Toledo Blue Stockings folding, while the late-entry Richmond Virginians returned to the Minor Leagues.
The National League's New York Gothams renamed as the New York Giants, and the American Association's Brooklyn Atlantics and Louisville Eclipse renamed as the Brooklyn Grays and Louisville Colonels, respectively.
The 1885 schedule consisted of 112 games for all teams in the American Association and National League, each of which had eight teams. Each team was scheduled to play 16 games against the other seven teams of their respective league. This continued the format put in place by the National League since the previous season. The American Association, due to downsizing from a twelve-team league to an eight-team league over the off season, took on this format. This would be the final season for this format, as the AA would implement a 140-game format and the NL a 126-game format the following season.
American Association Opening Day took place on April 18 featuring four teams, while National League Opening Day took place on April 30, with a game between the Chicago White Stockings and St. Louis Maroons. The American Association would see its final day of the regular season on October 5 with a game between the Brooklyn Grays and Philadelphia Athletics, while the National League would see its final day of the season on October 10, featuring four teams. The 1885 World's Championship Series took place between October 14 and October 24, though was originally supposed to extend to October 31.
The 1885 season saw the following rule changes:
Three teams hosted games at neutral sites, the Buffalo Bisons, Providence Grays, and St. Louis Maroons.
4 tie games (1 in AA, 3 in NL), which are not factored into winning percentage or games behind (and were often replayed again) occurred throughout the season.
The Baltimore Orioles and Philadelphia Athletics had one tie game each.
The St. Louis Maroons had three tie games. The Boston Beaneaters, Chicago White Stockings, and Philadelphia Quakers had one tie game each.
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The Chicago White Stockings leave Lakefront Park (where they played for seven seasons) and move to West Side Park, where they would go on to play for seven seasons, partway through .
For various reasons, three teams would play home games at neutral sites: