This article refers to the original incarnations of the Northern League, which operated between 1902 and 1971. For the more recent league, see Northern League (baseball, 1993–2010)

The Northern League was a name used by several minor league

Minor league baseball

Minor league baseball is a hierarchy of professional baseball leagues in the Americas that compete at levels below Major League Baseball and provide opportunities for player development. All of the minor leagues are operated as independent businesses...

 baseball organizations that operated off and on between 1902 and 1971 in the upper midwestern United States

Midwestern United States

The Midwestern United States is one of the four U.S. geographic regions defined by the United States Census Bureau, providing an official definition of the American Midwest....

 and Manitoba

Manitoba

Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...

, Canada. In total, there have been six incarnations of the Northern League, with the most recent beginning play in 1993 and ending after the 2010 season.
The Northern League name represented five leagues in this timeframe:

• First Northern League: 1902–05
  • Northern-Copper League 1906–08
  • Minnesota Wisconsin League 1909–11
  • Central International League 1912
• Second Northern League: 1908
• Third Northern League: 1913–17
• Fourth Northern League: 1933–42
• Fifth Northern League: 1946–71

The first Northern League operated between 1902 and 1905.