USNL: 1945-1946 (2 seasons)
All-black league used as a distraction while the Dodgers formulated and end to segregation in baseball.
NAL: 1937-1948 (12 seasons)
Organized by franchises located in the Midwest as competition to the Negro National League's eastern teams.
NNL: 1933-1948 (16 seasons)
Owners of 7 negro league teams ratified a constitution and organized a successful second Negro National League.
NEWL: 1932-1932 (1 season)
Eight teams joined in an ill-fated attempt to organize Negro baseball during the Great Depression.
NSL: 1932-1932 (1 season)
Several established teams joined the NSL, mainly from the collapsed Negro National League a year prior.
ANL: 1929-1929 (1 season)
An attempt to create a league by five surviving teams from the failed Eastern Colored League.
ECL: 1923-1928 (6 seasons)
Formed by several eastern teams that broke away from the midwest-based Negro National League.
NNL1: 1920-1931 (12 seasons)
The first organized and financially successful professional Negro baseball league.
NACB: 1907-1910 (4 seasons)
Formed to protect teams from unreliable managers, schedules, and rosters of past independent clubs.
IL: 1906-1906 (1 season)
League composed of a mix of white, Cuban and Negro league baseball teams in Pennsylvania, New Jersey and Delaware.
NCBL: 1887-1887 (1 season)
The second attempt to have a league consisting of all-black teams, predating the Negro National League by over three decades.
SLCB: 1886-1886 (1 season)
The first formal black league included teams from Atlanta, Charleston, Jacksonville, Memphis, New Orleans and Savannah.