Seven baseball circuits from the first half of the 20th century are now recognized as major leagues
| League | From | To |
|---|---|---|
| Negro National League (1) | 1920 | 1931 |
| Eastern Colored League | 1923 | 1928 |
| American Negro League | 1929 | |
| East-West League | 1932 | |
| Negro Southern League | 1932 | |
| Negro National League (2) | 1933 | 1948 |
| Negro American League | 1937 | 1948 |
