The Illinois flag is a simple representation of the Great Seal of Illinois against a white background. In 1969, the General Assembly voted to add the word "ILLINOIS" under the Great Seal of the flag. The State's name was added to the flag to ensure that people not familiar with the Great Seal of Illinois would still recognize the banner. Flag adopted 1915. Illinois anthem is “Illinois” written by C.H. Chamberlain and composed by Archibald Johnston. With this video you can see the flag and hear the anthem. Good for all students.