The Midwestern Collegiate Conference (now the Horizon League) was formed in 1979 by six NCAA Division I schools that originally dubbed themselves the Midwestern City 6, and officially the Midwestern City Conference (or MCC) soon thereafter. The charter members included Butler, Evansville, Loyola, Oklahoma City, Oral Roberts and Xavier. Marquette, an independent at the time of the league's formation, was one of two observing schools present during a preliminary meeting during the 73rd NCAA Convention in San Francisco on January 8, 1979; Creighton was the other school.

In 1985, the conference's name was altered slightly to Midwestern Collegiate Conference. Marquette announced that it will join the MCC, effective Sept. 1, 1988. The Warriors begin competition in some non-revenue sports immediately, while the remainder of the sports begin MCC play in 1989-90.

Marquette's tenure with the league was short-lived as they, along with St. Louis, announced on November 15, 1990 that they will be withdrawing from the league on June 30, 1991.

Other former members of the MCC include four charter members - Evansville, Oklahoma City, Oral Roberts, and Xavier - as well as Dayton, Duquesne, La Salle, Northern Illinois, Notre Dame, and St. Louis.

The conference again changed its name to the Horizon League on June 4, 2001, in part to avoid being confused with the Mid-Continent Conference. The current members of the Horizon League (as of the 2007-08 season) include two of the charter members - Butler and Loyola, (IL) - and Cleveland St., Detroit, Illinois-Chicago, Valparaiso, UW-Green Bay, UW-Milwaukee, Wright State, and Youngstown State.

For most of its existence it has generally been considered one of the top mid-major conferences in the country, particularly in men's basketball.

• 1989-90: 9-5 (league), 15-14 (overall), NIT (Loss to Penn State, 57-54)

Conference Tournament Results: Lost as #4 seed to #5 Evansville, 57-66

• 1990-91: 7-7 (league), 11-18 (overall)

Conference Tournament Results: Lost as #6 seed to #3 St. Louis, 82-92

• Largest Scoring Margin, League Game - 46, 82-36 victory over Loyola (IL) on 1/19/91
• Blocked Shots, League Season - 92, 1990-91
• Blocked Shots, All Games - 16 vs. Butler on 2/2/91
• Home Attendance (Average), All Games, Season - 13,433 (201,501 over 15 games), 1990-91
• Home Attendance (Average), League Games, Season - 13,324 (93,271 over 7 games), 1990-91
• Home Attendance, All Games - 16,761 vs. DePaul on 1/23/90
• Home Attendance, League Game - 14,988 vs. Dayton on 2/18/90
• Team Rebounding Margin, Season - +5.2, 1990-91
• Team 3-Point FG Percentage, Season - 39.7%, 1990-91
• Blocked Shots, League Season - 63 by Jim McIlvaine, 1990-91
• Blocked Shots, League Season Average - 4.5 by Jim McIlvaine, 1990-91
• Blocked Shots, All Games Season Average - 3.3 by Jim McIlvaine, 1990-91
• Three-Point Field-Goal Percentage, League Season Average - 47.4 by Mark Anglavar, 1990-91

• Tony Smith - 1989-90 First Team
• Trevor Powell - 1989-90 Second Team
• Damon Key - 1990-91 Newcomer Team

• Tony Smith - 1989-90 (Weeks of Dec. 10 and Jan. 21)
• Trevor Powell - 1989-90 (Week of Jan. 2); 1990-91 (Week of Dec. 9)

• 1979-80: Loyola (IL)
• 1980-81: Xavier
• 1981-82: Evansville
• 1982-83: Loyola (IL)
• 1983-84: Oral Roberts
• 1984-85: Loyola (IL)
• 1985-86: Xavier
• 1986-87: Evansville
• 1987-88: Xavier
• 1988-89: Evansville
• 1989-90: Xavier
• 1990-91: Xavier
• 1991-92: Evansville
• 1992-93: Xavier
• 1993-94: Xavier
• 1994-95: Xavier
• 1995-96: UW-Green Bay
• 1996-97: Butler
• 1997-98: Detroit
• 1998-99: Butler
• 1999-00: Butler
• 2000-01: Butler
• 2001-02: Butler
• 2002-03: Butler
• 2003-04: UW-Milwaukee
• 2004-05: UW-Milwaukee
• 2005-06: UW-Milwaukee
• 2006-07: Wright State
• 2007-08:

• 1979-80: Evansville, Ind. (Oral Roberts)
• 1980-81: Cincinnati, Ohio (Oklahoma City)
• 1981-82: Tulsa, Okla. (Evansville)
• 1982-83: Evansville, Ind. (Xavier)
• 1983-84: Chicago, Ill. (Oral Roberts)
• 1984-85: Tulsa, Okla. (Loyola, IL)
• 1985-86: Indianapolis, Ind. (Xavier)
• 1986-87: Indianapolis, Ind. (Xavier)
• 1987-88: Indianapolis, Ind. (Xavier)
• 1988-89: Dayton, Ohio (Xavier)
• 1989-90: Dayton, Ohio (Dayton)
• 1990-91: Dayton, Ohio (Xavier)
• 1991-92: Cincinnati, Ohio (Evansville)
• 1992-93: Indianapolis, Ind. (Evansville)
• 1993-94: Indianapolis, Ind. (Detroit)
• 1994-95: Dayton, Ohio (UW-Green Bay)
• 1995-96: Dayton, Ohio (Northern Illinois)
• 1996-97: Dayton, Ohio (Butler)
• 1997-98: Green Bay, Wis. (Butler)
• 1998-99: Chicago, Ill. (Detroit)
• 1999-00: Chicago, Ill. (Butler)
• 2000-01: Dayton, Ohio (Butler)
• 2001-02: Cleveland, Ohio (Illinois-Chicago)
• 2002-03: Milwaukee, Wis. (UW-Milwaukee)
• 2003-04: Milwaukee, Wis. (Illinois-Chicago)
• 2004-05: Milwaukee, Wis. (UW-Milwaukee)
• 2005-06: Milwaukee, Wis. (UW-Milwaukee)
• 2006-07: Dayton, Ohio (Wright State)
• 2007-08: