The Middle Atlantic League played from 1925 through 1951, with the exception of three seasons (1943-45) when the loop suspended operations during World War II. The MAL primarily featured clubs based in the U.S. states of Pennsylvania, Ohio and West Virginia, although it had a team in Maryland and, in its final season, one in New York. Its longest-tenured team, in Johnstown, Pennsylvania - the Johnnies - existed for 19 seasons. Its final champion was the 1951 Erie Sailors, an affiliate of the Washington Senators.
Throughout its 24-year history, the MAL was a Class C league, one rung up from the lowest classification, Class D.
Elmer M. Daily was president of the MAL through all 25 years of its existence.