Negro National League (1920–1931)
|No. of teams||24|
League history 
Led by Rube Foster, owner and manager of the Chicago American Giants, the NNL was established on February 13, 1920 by a coalition of team owners at a meeting in a Kansas City YMCA. The new league was the first African-American baseball circuit to achieve stability and last more than one season. At first the league operated mainly in midwestern cities, ranging from Kansas City in the west to Pittsburgh in the east; in 1924 it expanded into the south, adding franchises in Birmingham and Memphis.
The two most important east coast clubs, the Hilldale Club of Darby, Pennsylvania, and the Bacharach Giants of Atlantic City, were affiliated with the NNL as associate clubs from 1920 to 1922, but did not compete for the championship. In 1923 they and four other eastern teams formed the Eastern Colored League (ECL) and raided the NNL for many of its top players, including John Henry Lloyd, Biz Mackey, George Scales, George Carr, and Clint Thomas, and signing Oscar Charleston, and Reuben Currie in 1924. The war between the two leagues came to an end in 1924, when they agreed to respect each others contracts and arranged for the Colored World Series between their champions.
Difficulties and demise 
The NNL survived controversies over umpiring, scheduling, and what some perceived as league president Rube Foster's disproportionate influence and favoritism toward his own team. It also outlasted Foster's decline into mental illness in 1926, and its eastern rival, the ECL, which folded in early 1928. The NNL finally fell apart in 1931 under the economic stress of the Great Depression.
The Negro American League, founded in 1937 and including several of the same teams that played in the original Negro National League, would eventually carry on as the western circuit of black baseball. A separate Negro National League was organized in 1933, but eventually became concentrated on the east coast. To distinguish between the two unrelated leagues, they are usually referred to as the first Negro National League (or NNL I) and the second Negro National League (or NNL II).
Negro National League franchises 
- Chicago American Giants (1920–1931) – Known as the Chicago Columbia Giants in 1931.
- Chicago Giants (1920–1921)
- Cuban Stars (1920–1930) – Known as the Cincinnati Cubans in 1921.
- Dayton Marcos (1920, 1926)
- Detroit Stars (1920–1931)
- Indianapolis ABCs (1920–1924, 1925–1926) – Dropped from league mid-season 1924 but returned the following season.
- Kansas City Monarchs (1920–1931)
- St. Louis Giants (1920–1921) – Replaced by St. Louis Stars in 1922, which was virtually the same team with new owners.
- St. Louis Stars (1922–1931) – Replaced the St. Louis Giants.
- Columbus Buckeyes (1921)
- Cleveland Tate Stars (1922–1923) – Dropped out mid-season 1923.
- Toledo Tigers (1923) – Mid-season replacement for Cleveland Tate Stars.
- Pittsburgh Keystones (1922)
- Milwaukee Bears (1923)
- Birmingham Black Barons (1924–1925, 1927–1930)
- Cleveland Browns (1924)
- Memphis Red Sox (1924–1925, 1927–1930) – Mid-season replacement in 1924 for Indianapolis ABCs.
- Cleveland Elites (1926) – Closely related to both Cleveland Hornets and Cleveland Tigers.
- Cleveland Hornets (1927) – Closely related to both Cleveland Elites and Cleveland Tigers.
- Cleveland Tigers (1928) – Closely related to both Cleveland Hornets and Cleveland Elites.
- Nashville Elite Giants (1930) – Became Cleveland Cubs for 1931 season.
- Cleveland Cubs (1931) – Returned to Nashville in 1932 after NNL folded.
- Indianapolis ABCs (2nd team) (1931)
- Louisville White Sox (1931)
Member timeline 
- 1920: Formation of NNL consisting of 8 teams — Chicago American Giants, Detroit Stars, Kansas City Monarchs, Indianapolis ABCs, St. Louis Giants, Cuban Stars, Dayton Marcos and Chicago Giants.
- 1921: Dropped Dayton Marcos; Added Columbus Buckeyes.
- 1922: Dropped Columbus Buckeyes, Chicago Giants, St. Louis Giants; Added Cleveland Tate Stars, Pittsburgh Keystones, St. Louis Stars.
- 1923: Dropped Cleveland Tate Stars (mid-season), Pittsburgh Keystones; Added Toledo Tigers (mid-season), Milwaukee Bears.
- 1924: Dropped Toledo Tigers, Milwaukee Bears, Indianapolis ABCs (mid-season); Added Cleveland Browns, Birmingham Black Barons, Memphis Red Sox (mid-season).
- 1925: Dropped Cleveland Browns; Added Indianapolis ABCs.
- 1926: Dropped Memphis Red Sox, Birmingham Black Barons; Added Cleveland Elites, re-added Dayton Marcos.
- 1927: Dropped Dayton Marcos, Indianapolis ABCs; Re-added Birmingham Black Barons, Memphis Red Sox.
- 1929: Dropped Cleveland Tigers.
- 1930: Added Nashville Elite Giants.
- 1931: Dropped Memphis Red Sox, Birmingham Black Barons, Cuban Stars; Added Louisville White Sox, (new) Indianapolis ABCs. League fell apart before season end.
League champions 
Pennant winners 
From 1920 through 1924, and also in 1929 and 1931, the team in first place at the end of the season was declared the Pennant winner. Due to the unorthodox nature of the schedule (and little incentive to enforce it), some teams frequently played many more games than others did in any given season. This led to some disputed championships and two teams claiming the title. Generally, the team with the best winning percentage (with some minimum number of games played) was awarded the Pennant, but other times it was the team with the most victories. The "games behind" method of recording standings was uncommon in most black leagues.
- 1920 – Chicago American Giants
- 1921 – Chicago American Giants
- 1922 – Chicago American Giants
- 1923 – Kansas City Monarchs
- 1924 – Kansas City Monarchs‡
- 1925 – Kansas City Monarchs†‡
- 1926 – Chicago American Giants†‡
- 1927 – Chicago American Giants†‡
- 1928 – St. Louis Stars†
- 1929 – Kansas City Monarchs
- 1930 – St. Louis Stars†
- 1931 – St. Louis Stars (season did not finish; Stars had best record among league members and were declared the champions, though non-member Pittsburgh Crawfords disputed title)
† – Pennant was decided via a split-season schedule with the winner of the first half of the season playing the winner of the second half of the season.
‡ – Pennant winner went on to play in the Colored World Series.
League play-offs 
From 1925 through 1928, and again in 1930, the NNL split the season into two halves. The winner of the first half played the winner of the second half for the league Pennant. As mentioned above, disputes also occurred in the split season finishes.
- 1925 – Kansas City Monarchs (first half champions) beat St. Louis Stars (second half champions), 5 games to 3 games
- 1926 – Chicago American Giants (2nd half) beat Kansas City Monarchs (1st half), 5 games to 4 games
- 1927 – Chicago American Giants (1st half) beat Birmingham Black Barons (2nd half), 4 games to 0 games
- 1928 – St. Louis Stars (1st half) beat Chicago American Giants (2nd half), 5 games to 4 games
- 1930 – St. Louis Stars (1st half) beat Detroit Stars (2nd half), 4 games to 3 games
Colored World Series 
For the duration of the league, a Colored World Series took place four times, from 1924 through 1927. The NNL Pennant winner met the champion of the rival Eastern Colored League. Three out of the four years, the Negro National League team (below in bold) prevailed.
- 1924 – Kansas City Monarchs beat Hilldale Club, 5 games to 4 games (1 tie)
- 1925 – Hilldale Club beat Kansas City Monarchs, 5 games to 1 game
- 1926 – Chicago American Giants beat Atlantic City Bacharach Giants, 5 games to 4 games (2 ties)
- 1927 – Chicago American Giants beat Atlantic City Bacharach Giants, 5 games to 3 games (1 tie)
- Holway, John B. (2001), The Complete Book of Baseball's Negro Leagues: The Other Half of Baseball History, Fern Park, FL: Hastings House, ISBN 0-8038-2007-0