The 1880 major league baseball season was contested from May 1 through October 1, 1880, and saw the Chicago White Stockings as the pennant winner of the fifth season of the National League. There was no postseason.
The 1880 season is known for the first two major league perfect games in history, as well as being the only perfect games in the 19th century. Thrown by Lee Richmond and John Ward, these two perfect games were thrown in the span of five days, the shortest amount of time between two perfect games (the next closest is currently 20 days between Dallas Braden's May 9 and Roy Halladay's and May 29, 2010 perfect games). A perfect game would not be seen again in the Major Leagues for 24 years when Cy Young threw his perfect game in .
Over the off-season, the Cincinnati Reds and Syracuse Stars disbanded, and were replaced by the Cincinnati Stars and Worcester Worcesters. This would be the Stars' only major league season.
The 1880 schedule consisted of 84 games for all eight teams of the National League. Each team was scheduled to play 12 games against the other seven teams in the league. This continued the format put in place since the previous season and would be used until .
Opening Day took place on May 1 featuring all eight teams. The final day of the season was on October 1, featuring a doubleheader between the Providence Grays and Worcester Worcesters.
The 1880 season saw the following rule changes:
An asterisk (*) denotes the ballpark a team played the minority of their home games at
Eight tie games, which are not factored into winning percentage or games behind occurred throughout the season (though standings were determined by total wins, not winning percentage).
The Buffalo Bisons, Cincinnati Stars, and Providence Grays had three tie games each. The Boston Red Caps, Chicago White Stockings, and Worcester Worcesters had two tie games each. The Cleveland Blues had one tie game.
The National League saw two teams join for the 1880 season:
The Troy Trojans leave the Putnam Grounds (where they played their inaugural seasons) and move to the Haymakers' Grounds, where they would play for two seasons through .
The Troy Trojans begin to host a few games at Riverside Park in nearby Greenbush, New York, playing on September 11.