From 1981-2000, the contest was two divisions: A (750 or less students) and AA (751+ students)

 Division ADivision AA
1981Red BudNew Trier East
1982SpartaNew Trier
1983SpartaNew Trier
1984SpartaNew Trier
1985SpartaNew Trier
1986OblongNew Trier
1987SpartaNew Trier
1988SpartaNew Trier
1990Johnston CityIL Math/Science Academy
1991OblongAdlai E Stevenson
1992Johnston CityIL Math/Science Adademy
1993SpartaIL Math/Science Academy
1994SpartaNaperville North
1995SpartaNaperville North
1996SpartaNaperville North
1997SpartaIL Math/Science Academy
1998SpartaNaperville North
1999University of Chicago LabNaperville North
2000OblongNaperville North

In 2001, the contest moved to four divisions.

 Division 1ADivision 2ADivision 3AADivision 4AA
2001OblongVernon HillsGlenbrook NorthNaperville North
2002Johnston CityUniversity of Chicago LabFenwickNaperville North
2003Johnston CityHerrinLibertyvilleNaperville North
2004Johnston CityWalter Payton College PrepLibertyvilleNaperville North
2005Johnston CityWalter Payton College PrepBenet AcademyNaperville North
2006Johnston CityWalter Payton College PrepGlenbard SouthNaperville North
2007CornerstoneUniversity of Chicago LabWalter Payton College PrepNaperville North
2008CornerstoneUniversity of Chicago LabVernon HillsIL Math/Science Academy
2009CornerstoneUniversity of Chicago LabVernon HillsIL Math/Science Academy
2010CornerstoneUniversity of Chicago LabWalter Payton College PrepIL Math/Science Academy
2011CornerstoneUniversity of Chicago LabWalter Payton College PrepNaperville North
2012CornerstoneMortonBenet AcademyIL Math/Science Academy
2013CornerstoneUniversity of Chicago LabLibertyvilleWhitney Young
2014CornerstoneUniversity of Chicago LabVernon HillsWhitney Young
2015CornerstoneUniversity of Chicago LabLibertyvilleAdlai E Stevenson
2016CornerstoneMahomet-SeymourLibertyvilleNaperville North
2017CornerstoneMahomet-SeymourGlenbrook NorthNaperville North
2018CornerstoneLake Forest AcademyGlenbrook NorthNaperville North
2019CornerstoneMahomet-SeymourGlenbrook NorthNaperville North