| Use | Civil and state flag |
|---|---|
| Proportion | 3:5 |
| Adopted | July 6, 1915 (initial version) September 17, 1969 (alteration) |
| Design | A state seal above the word Illinois in blue on a white field. |
| Designed by | Sharon Tyndale |
| Great Seal of the State of Illinois | |
|---|---|
| Details | |
| Armiger | State of Illinois |
| Adopted | 1868 |
| Supporters | 7 |
| Motto | "State Sovereignty, National Union" |
The flag and Seal of the State of Illinois are the state's official symbols. The seal is used on official state documents. The top part of the seal has the words "Seal of the State of Illinois" The date Aug. 26th 1818 (on which Illinois was declared a U.S. State) is at the bottom of the seal. A bald eagle is in the middle.
Secretary of the State Sharon Tyndale made an updated version for the seal in 1867.
The state's flag was chosen in 1915. The flag has the state seal of Illinois surrounded by white. This original design was changed in 1961 to add the name of the state at the bottom of the flag. It originally did not have the word Illinois at the bottom of the flag. But in 1969, the state word was added to the flag. The 1969 edition of Illinois' flag is the version that was used from then on.

On December 10th, 2024, 10 finalists for a new Illinois state flag were released. They were chosen from thousands of designs in a flag redesign competition to be put to a public vote from January-February 2025. In addition to those designs, people could vote to adopt the Centennial Flag, the Sesquicentennial Flag, or the current flag. When the votes were counted, 43% voted to keep the current flag.