The longest tenured version of the Interstate League was the last incarnation and was one of the few mid-level minor leagues to operate continuously during the World War II period .
The last incarnation played in the Middle Atlantic States from 1939 through 1952 .
The longest tenured version of the Interstate League was the last incarnation , which played in the Middle Atlantic States from 1939 through 1952 , and was one of the few mid-level minor leagues to operate continuously during the World War II period .