| Girls Basketball Undefeated Teams | |||
| Year | Class | School | Wins |
|---|---|---|---|
| 2009 | 8-2A | Peoria St. Vincent de Paul | 28 |
| 2009 | 8-4A | Rochester | 26 |
| 2009 | 7-3A | Litchfield | 26 |
| 2008 | 8-4A | Champaign Jefferson | 28 |
| 2008 | 8-3A | Paris Mayo | 28 |
| 2008 | 7-4A | Rochester | 27 |
| 2008 | 7-2A | Springfield Blessed Sacrament | 27 |
| 2007 | 7-2A | Glasford Illini Bluffs | 26 |
| 2007 | 7-1A | Jacksonville Our Saviour | 25 |
| 2007 | 7-3A | Eureka | 24 |
| 2007 | 7-4A | Springfield Franklin | 23 |
| 2006 | 7-3A | Paris Mayo | 28 |
| 2006 | 8-2A | Normal Epiphany | 28 |
| 2006 | 7-4A | Quincy | 25 |
| 2005 | 7A | Normal Epiphany | 27 |
| 2005 | 7AA | Washington MS | 25 |
| 2004 | 8AA | Chatham Glenwood | 25 |
| 2003 | 7AA | Chatham Glenwood | 27 |
| 2003 | 8AA | Bloomington JHS | 24 |
| 2002 | 7A | Martinsville | 25 |
| 2002 | 8AA | Hillsboro | 26 |
| 2002 | 8A | Springfield St. Agnes | 27 |
| 2001 | 7AA | Teutopolis | 25 |
| 2001 | 8AA | Washington Central | 25 |
| 2000 | 7A | Springfield Blessed Sacrament | 24 |
| 2000 | 8A | Lincoln Carroll Catholic | 24 |
| 1998 | 7A | Carthage | 28 |
| 1998 | 8AA | Urbana MS | 23 |
| 1998 | 7AA | Normal Parkside | 25 |
| 1998 | 8A | Carthage | 25 |
| 1997 | 7A | Roanoke Benson | 22 |
| 1997 | 7AA | Springfield Grant | 22 |
| 1995 | 8A | Carthage | 20 |
| 1995 | 7A | Bowen Southwestern | 24 |
| 1995 | 8AA | Pittsfield Higbee | 25 |
| 1995 | 7AA | Pana | 25 |
| 1994 | 7A | Paris Crestwood | 22 |
| 1994 | 8A | Carthage | 21 |
| 1994 | 8AA | Mt. Zion | 24 |
| 1993 | 8AA | Taylorville | 23 |
| 1993 | 7AA | Mt. Zion | 21 |
| 1993 | 7A | Paris Crestwood | 22 |
| 1992 | 8AA | Quincy | 24 |
| 1992 | 7AA | Springfield Franklin | 20 |
| 1991 | 7AA | Jerseyville Illini | 23 |
| 1990 | 8AA | Springfield Franklin | 21 |
| 1990 | 8A | Hamilton | 22 |
| 1988 | 8G | Mattoon | 22 |
| 1987 | 8G | Springfield Washington | 22 |
| 1987 | 7G | Canton Ingersoll | 21 |
| 1986 | 8G | Seneca | 23 |
Class HistoryThe IESA sanctioned girls basketball in 1979. There was one class of girls basketball until 1986 when the activity was split into 7th and 8th grade classes. From 1990-2005, the Association adopted the format of 7th and 8th grade play based upon a school's enrollment (7A, 7AA, 8A and 8AA). Starting in 2006, the Association adopted a four class system in each grade level (7-1A, 7-2A, 7-3A, 7-4A, 8-1A, 8-2A, 8-3A and 8-4A). The current classification system assigns 25% of the schools to each of the four classes. |