The 1892 major league baseball season began on April 12, 1892. Unique to National League history, the season was organized into a split season format, with July 14 being the split date between the two half seasons. The regular season ended on October 15, with the Boston Beaneaters as the pennant winner of the National League overall, as well as the first-half champions, with the Cleveland Spiders as second-half champions. The postseason began with Game 1 of the eighth and final World's Championship Series on October 17 and ended with Game 6 on October 24. Aside from a tie game, the Beaneaters swept the Spiders with five wins in the best-of-nine playoff, and therefore winner of the final Dauvray Cup. This was Boston's only pre-modern championship.
The 1892 season saw the return of a postseason championship series (albeit a one-off of this format), following the demise of the American Association. The one-off was the first since the 1890 World's Championship Series. The next championship series would take place in via the Temple Cup.
The demise of the American Association saw four of its teams merged into the National League, including the Baltimore Orioles, Louisville Colonels, St. Louis Browns, and Washington Statesmen (renamed as the Washington Senators). The four other American Association clubs active at the end of the previous season, the Boston Reds, Columbus Solons, Milwaukee Brewers, and Philadelphia Athletics), saw their owners paid $135,000 () and their players dispersed to the surviving clubs.
The 1892 schedule consisted of 154 games for the twelve teams of the National League. Each team was scheduled to play 12 games against the other eleven teams in the league. This replaced the 140-game, 20-games-each against seven-teams format previously used by the National League since 1888 and defunct-American Association since 1886. The 140-game format would return in .
Opening Day took place on April 12 featuring all twelve teams. Each half of the season was split by an off day on July 14. The final day of the season was on October 15 and also featured all twelve teams. The 1892 World's Championship Series took place between October 17 and October 24.
The 1892 season saw the following rule changes:
18 tie games, which are not factored into winning percentage or games behind (and were often replayed again), occurred throughout the season. Values in parenthesis show first-half and second-half ties.
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Having previously split their time in two ballparks for the season, the Chicago Colts permanently leave the site of West Side Park after playing there for seven seasons since in favor of South Side Park.