The Northern Indiana Conference (NIC) is a high school athletic conference that was founded in 1927 and spanned from as far west as Hammond and Gary to South Bend/Mishawaka and Elkhart to the east and south to Plymouth. Since its start in 1927, a total of 32 separate schools have at one time called the NIC home. From its inception until 1963, the conference had been divided into East and West divisions. The West Division (as well as Valparaiso) left to form the Northwestern Conference in 1963. With membership dwindling to 7 members by the 1970s, the conference added former members of the Northern Indiana Valley Conference to its ranks. Currently, every former NIVC member is now a part of the NIC except for South Bend Jackson, which closed in 1973, and South Bend LaSalle, which joined the NIC in 1977, but closed in 2001.

Like the Southern Indiana Athletic Conference, the NIAC was also a superconference that spanned several counties, and a lot of driving miles, for a period between 1940 and 1965. Throughout the 1970s the membership dwindled as many schools left to form new conferences. From 1995 to 2015 the two conferences share the same setup with 7 or 8 schools in one county, 8 in this case from St. Joseph County and 1 from an adjacent county, Elkhart in this case. This will change in 2015, as four schools from the folding Northern State Conference will join, making a 13 school conference.^[1] This will also expand the conference footprint into two counties formerly represented in the NIAC: LaPorte (last represented in 1995) and Marshall (last represented in 1930). 2020 will bring more change, as Elkhart Central merges with former member Elkhart Memorial to form Elkhart high school, and Mishawaka leaves for the Northern Lakes Conference, taking Memorial's spot in that league.^[2]

1. Elkhart was known as Elkhart Central between 1972-2020. In 2020, Elkhart Central consolidated with Elkhart Memorial.
2. Played concurrently in NIC and NIVC 1974-78.
3. South Bend St. Joseph was known as South Bend St. Joseph's until 2012.

1. East Chicago Washington was known as East Chicago until 1928.
2. Michigan City Elston was known as Michigan City until 1972.
3. South Bend Central was known as South Bend until 1930.
4. Played concurrently in the NIC and FWCS their entire membership in the NIC.
5. Played concurrently in the NIC and NLC 1999-2000.
6. Played concurrently in the NIC and NIVC 1976-78.

Membership timeline

Main rivalries:

• Riley Wildcats vs. Penn Kingsmen
• Clay Colonials vs. Washington Panthers
• Penn Kingsmen vs. Mishawaka Cavemen* (often called "The Backyard Brawl")
• St. Joseph High School vs. Marian Knights (often called "The Holy War")
• Riley Wildcats vs. Adams Eagles
• New Prairie Cougars vs. La Porte* Slicers
• Bremen Lions vs. Jimtown Jimmies (Rivalry published in November 1994 issue of Sports Illustrated magazine "Unrivaled Rivalries")

Notable sub-rivalries

• Riley vs. Clay
• Adams vs. Clay
• St. Joseph vs. Penn
• Riley vs. Marian (often called "The South Side Brawl")
• Jimtown vs. NorthWood* (often called "The Border War")
• Bremen vs. Triton* (also often called "The Border War")
• Penn vs. Fort Wayne Snider*
• Marian vs. Mishawaka* (often called "The Civil War")
• St. Joseph vs. Clay
• Mishawaka* vs. Washington
• Marian vs. Penn (baseball only)
• St. Joseph vs. Culver Military Academy (hockey and lacrosse only)*°
• Mishawaka vs. Clay (football only)
• Mishawaka vs. Adams (basketball only)

Former rivalries

• Elkhart Central Blue Blazers vs. Elkhart Memorial Crimson Chargers* (often called "The Battle of Elkhart")
• Lasalle vs Washington.

(Asterisk indicates non-member of NIC)

(Degree indicates a non-NIC sanctioned sport)

• Hoosier Hysteria
• Largest high school gyms in the United States

• Northern Indiana Football History
• Indiana High School Athletic Association
• List of high school athletic conferences in Indiana
• Indiana big school football champions