A Silver color metal and enamel device 1 7/32 inches (3.10 cm) in height overall consisting of a shield blazoned: "Gules, a pall reversed of chains voided of the field, in the first a winged foot, in the second a set of crossed drumsticks surmounted by a mask of comedy, in the third a cogwheel superimposed on the dexter of an open book all Or. Supporting the shield two cougars guardant Argent. Attached below the shield, a Maroon scroll inscribed "McLEAN COUNTY" in Silver.
Maroon, gold, white and red are the school colors. Red (maroon) reflects the combining of the three schools' primary colors that now comprise McLean County High School. Gold (yellow) symbolizes honor an attribute the cadets reflect in keeping high moral standards of behavior. Silver (white) conveys maturity, a trait the cadets' show in their decisions and manners. Red alludes to zeal, an attribute the cadets demonstrate in their approach to any task presented to them. The three links of chain joined together signify the three community high schools combined into one county high school. The winged foot, mask of comedy with drumsticks and cogwheel with open book portrays health and physical education, the arts; science and math respectively. The cougars are the school's mascot and represent courage and strength.
The shoulder loop insignia was authorized 18 September 2014.