Orioles

Atlantics

Red
Stockings

Buckeyes

Hoosiers

Eclipse

Metropolitans

Athletics

Alleghenys

      Virginians

Browns

Blue Stockings

Nationals

Locations of teams for the 1884 American Association season
American Association

Beaneaters

Bisons

White Stockings

Blues

Wolverines

Gothams

Quakers

   Grays

Locations of teams for the 1884 National League season
National League

Mountain Citys

Monumentals

Reds

Browns*

Stogies*

Outlaw Reds

Cowboys

Brewers

       Keystones

Maroons

Saints

Nationals

Quicksteps

Locations of teams for the 1884 Union Association season
Union Association
*Chicago Browns moved to Pittsburgh mid-way through the season as the Pittsburgh Stogies.

The 1884 major league baseball season began on April 17, 1884. The National League and American Association's regular seasons ended on October 15, with the Providence Grays and New York Metropolitans as the NL and AA pennant winners, respectively. The newly founded Union Association regular season ended on October 19, with the St. Louis Maroons as the UA pennant winner. The postseason between the AA and NL began with Game 1 of the first World's Championship Series (the first inter-league championship game of its kind in the Major Leagues) on October 23 and ended with Game 3 on October 25, in what was a best-of-five-playoff. The Grays swept the Metropolitans in three games, capturing their first World's Championship Series.

Prior to the 1884 season, in September 1883, the Union Association was formed, in direct contravention to the reserve rule (that a ballplayer could be reserved by a team) of the 1883 National Agreement (a.k.a. Tripartite Agreement) signed between the National League, American Association, and minor league Northwestern League.^[1] In response to formation of the UA, the AA expanded their league from an eight teams to twelve teams to undermine the weak footing the UA had, as UA teams were mostly in cities that already had established AA and NL teams.^[2]

The American Association expansion saw the minor league Brooklyn Grays of the Inter-State Association of Professional Baseball Clubs join as the Brooklyn Atlantics (today's Los Angeles Dodgers) and the Toledo Blue Stockings join from the minor league Northwestern League, as well as the establishment of the Indianapolis Hoosiers and Washington Nationals. The latter played their last game on August 2, and were replaced by the minor league Eastern League's Richmond Virginians to finish Washington's schedule.

The Union Association was largely unstable throughout its only year in existence (though confidence in the league remained high), as three of its founding teams would not make it to the end of the season.^[2] The Altoona Mountain Citys folded on May 31, and were replaced by the Kansas City Cowboys on June 7. The Philadelphia Keystones folded on August 7, and were replaced by the Eastern League's Wilmington Quicksteps. The Chicago Browns relocated to Pittsburgh as the Pittsburgh Stogies following their August 21 game. The Quicksteps would fold on September 15, while the Stogies would fold just three days later. On September 27, the Milwaukee Brewers and St. Paul Apostles (now renamed the St. Paul Saints) were recruited from the Northwestern League to finish the Philadelphia / Wilmington and Chicago/Pittsburgh schedules, respectively.

The 1884 season featured the second African American player in the major leagues (following William Edward White five years prior), debuting May 1 and playing 42 games for the Toledo Blue Stockings of the American Association. During his tenure, he faced abuse from other players (including teammates), fans, and the press, and even threats of being mobbed by 75 men before a road trip to Richmond, Virginia, before being released due to injury on September 29, prior to the road trip.^[3] His brother Weldy Walker played on the Toledo Blue Stockings for five games between July and August, becoming the third African American in the major leagues.

While it wouldn't be until 1887 that the color barrier was formally implemented (thanks to threats to not play from Chicago White Stockings manager Cap Anson and the general racism in society), the color barrier would not begin breaking until the Brooklyn Dodgers called up Jackie Robinson in 1947, 63 years after Walker's last game.^[4]

The 1884 schedule consisted of 110 games for all teams in the American Association, which had twelve active teams, and 112 games for all teams in the National League and Union Association, each of which had eight active teams. Each AA team was scheduled to play 10 games against the other eleven teams in their league, and each of NL & UA teams were scheduled to play 16 games against the other seven teams of their respective league. The National League increased its total games per team from 98 to 112, 14 games to 16 games per seven opponents. The new Union Association copied this format. Meanwhile, the American Association, expanding from eight to twelve teams, changed from the 98-game format to the 110-game format. The National League would continue to use their 112-game format through the following season, while the American Association would copy the NL format.

Union Association Opening Day took place on April 17 featuring six teams, while American Association and National League Opening Days took place on May 1, featuring all twelve and all eight teams, respectively. The Union Association would see its final day of the regular season on October 19 featuring four teams, while the American Association and National League would see their final day of the regular season on October 15 featuring all twelve teams and four teams, respectively.^[5] The 1884 World's Championship Series took place between October 23 and October 25.

The 1884 season saw the following rule changes:

• In the National League all restrictions on the delivery of a pitcher were removed.^[6] This lifting of restrictions enabled pitchers to throw above the shoulder during pitch delivery.^[7] The American Association would follow suit the following year.
• In the National League, six balls became a base on balls, down from seven. The American Association keeps the rule at seven balls.^[8]
• In the American Association, a hit by pitch rule was implemented, when a batter was "solidly and bodily hit by a pitched ball when he cannot apparently avoid it." The National League would not implement a hit by pitch rule until 1887.^[8]

An asterisk (*) denotes the ballpark a team played the minority of their home games at
A dagger (†) denotes a team that folded mid-season
A double dagger (‡) denotes a team joined mid-season

Four teams played in four neutral or alternate sites in which they were treated as the home team. Meanwhile, blue laws restricted Sunday activities in several localities, causing the Indianapolis Hoosiers 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.

35 tie games (19 in AA, 10 in NL, 6 in UA), which are not factored into winning percentage or games behind (and were often replayed again), occurred throughout the season.

Any team shown in small text indicates a previous team a player was on during the season.
Any team shown in italics indicates a team a player was on from a different league. Any stat from said different league is not calculated to determine the league leader.

• Jim O'Rourke (BUF):
  • O'Rourke hit for his first cycle and second in franchise history, on June 16 against the Chicago White Stockings.^[21]

• Ned Williamson (CHI):
  • Became the first player to hit three home runs in one game in a 12–2 win over the Detroit Wolverines on May 30.

• Al Atkinson (PHA):
  • Atkinson threw his first career no-hitter and the first no-hitter in franchise history, by defeating the Pittsburgh Alleghenys 10–1 on May 24.^[22]
• Ed Morris (COL):
  • Morris threw his first career no-hitter and the first no-hitter in franchise history, by defeating the Pittsburgh Alleghenys 5–0 on May 29.^[22]
• Frank Mountain (COL):
  • Mountain threw his first career no-hitter and the second no-hitter in franchise history, by defeating the Washington Nationals 12–0 on June 5.^[22]
• Larry Corcoran (CHI):
  • Corcoran threw his third career no-hitter and the third no-hitter in franchise history, by defeating the Providence Grays 6–0 on June 27.^[22]
• Pud Galvin (BUF):
  • Galvin threw his second career no-hitter and the second no-hitter in franchise history, by defeating the Detroit Wolverines 18–0 on August 4.^[22]
• Dick Burns (COR):
  • Burns threw his first career no-hitter, first no-hitter in franchise history, and first no-hitter in Union Association history, by defeating the Kansas City Cowboys 3–1 on August 26.^[22]
• Ed Cushman (MIL):
  • Cushman threw his first career no-hitter and the first no-hitter in franchise history, by defeating the Washington Nationals 5–0 on September 28.^[22]
• Sam Kimber (BRO):
  • Kimber threw his first career no-hitter and the first no-hitter in franchise history, in a scoreless, 10-inning tie against the Toledo Blue Stockings on October 4. Kimber walked five and struck out six. It is the first no-hitter that did not result in a win and the only no-hitter to result in a tie.^[23][24]

• Charlie Sweeney (PRO):
  • Set a Major League record for most strikeouts in a single game, throwing 19 strikeouts in a 2–1 win over the Boston Beaneaters on June 7.^[25][26] The record, in a nine-inning game, would not be broken until Roger Clemens threw 20 strikeouts in 1986.
• Hugh Daily (CUN):
  • Tied a Major League record for most strikeouts in a single game, throwing 19 strikeouts in a 10–4 win over the Boston Reds on July 7.^[27][28]
• Henry Porter (MIL):
  • Set a Major League record for most strikeouts in a single game while still losing, throwing 18 strikeouts in a 5–4 loss to the Boston Reds on October 3.^[29][30] This record will be broken in 1969 by Steve Carlton.
• Charles Radbourn (PRO):
  • Set a Major League record for most wins in a single season, winning 60 games.^[31] It is considered an unbreakable record, because no pitcher has made 37 or more starts in a season since Greg Maddux did so in 1991.^[32]

The 1884 season saw the single-season Union Association form, and with it, there were initially eight new teams in eight venues:

• The Altoona Mountain Citys played at Columbia Park.
• The Baltimore Monumentals played at the Belair Lot.
• The Boston Reds played at Dartmouth Street Grounds.
• The Chicago Browns played at South Side Park.
• The Cincinnati Outlaw Reds played at Bank Street Grounds.
• The Philadelphia Keystones played at Keystone Park.
• The St. Louis Maroons played at Union Base Ball Park.
• The Washington Nationals played at the Capitol Grounds.

Four of these teams folded, one of which relocated cities prior to folding. All four were replaced with other teams who played in different venues:

• The Altoona Mountain Citys folded on May 31, and on June 7 were replaced with the Kansas City Cowboys and play at Athletic Park.
• The Philadelphia Keystones folded on August 7, and on August 18 were replaced with the Wilmington Quicksteps and play at Union Street Park.
• After the Chicago Browns played their August 22 game away, they relocated to Allegheny, Pennsylvania and rebranded as the Pittsburgh Stogies in time for their next five home games at Exposition Park (the second iteration that the Pittsburgh Alleghenys played early the previous season), from August 25 through August 30.
• The Wilmington Quicksteps folded on September 15 and the Pittsburgh Stogies folded on September 18. On September 27 the two vacant spots were filled respectively by minor league teams of the Milwaukee Brewers, playing at Wright Street Grounds, and the St. Paul Saints, playing at West Seventh Street Park (though never played a major league game there).

The 1884 season saw the American Association with two new teams:

• The Brooklyn Atlantics played at Washington Park.
• The Richmond Virginians, following the collapse of the Washington Nationals following their August 2 loss, began playing Major League games on August 5 at Virginia Base-Ball Park.

The 1884 season saw four teams relocate to new ballparks:

• The Buffalo Bisons leave Riverside Park (where they played for five seasons) and move to Olympic Park, where they would go on to play for two seasons through 1885, before continuing on as a minor league team.
• The Cincinnati Red Stockings leave Bank Street Grounds (where they played for three seasons) and move to American Park, where they would go on to play for 18 seasons through 1901.
• The New York Metropolitans attempted to leave the Polo Grounds at the start of the season, playing the majority of home games at nearby Metropolitan Park. However, this stay would not last. Aside from a five-game stretch from July 17–22 where they returned to the Polo Grounds, they permanently left the park after their August 23 game. Prior to leaving, the park had been labeled "The Dump" by players and other observers (especially sports reporters working for the Brooklyn Eagle). Following a long road trip, their next home game saw them move back to the Polo Grounds for another 15 games for the rest of the season, where they would stay for the following season.^[33][34]
• The Pittsburgh Alleghenys leave Exposition Park (where they played for two seasons) and move to Recreation Park, where they would go on to play for seven seasons through 1890.

For various reasons, three teams would play home games at neutral sites:

• The Baltimore Monumentals played at Monumental Park in Baltimore, Maryland on August 25.^[35]
• The Cincinnati Red Stockings played at Washington Park at the home of the Brooklyn Atlantics in Brooklyn, New York, on October 10.^[36]
• The Pittsburgh Stogies played at Belair Lot at the home of the Baltimore Monumentals in Baltimore, Maryland.^[37]
• The Toledo Blue Stockings played at the Tri-State Fair Grounds in Toledo, Ohio, on September 13.^[38]

The Indianapolis Hoosiers hosted 11 Sunday games at the Bruce Grounds north of Indianapolis city limits in Center Township on May 18, 25, June 22, 29, July 6, 13, 20, August 3, 10, 31, and September 21.^[39]

• 1884 in baseball (Events, Births, Deaths)

• 1884 Major League Schedule at Baseball Reference