1884 St. Louis Maroons season

The 1884 St. Louis Maroons baseball team finished with a 94–19 record and won the championship of the new Union Association (UA). After the season, the UA folded and the Maroons joined the National League; they were the only UA team to continue past the 1884 season.

To this day, the Maroons' .832 winning percentage hasn't been matched by a professional baseball team; however, due to the relatively low amount of games played, as well as the debate over the classification of the Union Association as a "major league," the 1884 St. Louis Maroons are not usually mentioned in the conversation of baseball teams with the best single-season records of all time. This team also set the record for the best start to a season in baseball history, going 20–0 before losing 8-1 to the Boston Reds on May 24, in their 21st game of the season.

The Maroons scored 887 runs while allowing 429, for a run differential of +458, the best in major-league history, as records and statistics of the UA are recognized by Major League Baseball (MLB).

The team was back in the news in 2015, when the Golden State Warriors started the 2015–16 season with an NBA-record 24 straight wins; this surpassed the Maroons' 20–0 start, which was previously the record for the four major professional sports leagues in the United States.

Starters by position
''Note: Pos = Position; G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs''

Other batters
''Note: G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs''

Starting pitchers
Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts

Relief pitchers
Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts