The Illinois state flag has a white background on which the Great Seal of Illinois is centered. A red banner outlined in white with a black border is held in the beak of an eagle. On the banner are the words of the state motto - "State Sovereignty, National Union". The word 'Sovereignty' is upside down and 'State' at the bottom to symbolize the state's fight and victory against state sovereignty during the Civil War. The dates on the rocks on which the eagle is perched, 1818 and 1868, represent the year Illinois became a state and the year in which the Great Seal was redesigned. The shield in the eagle's talons has thirteen stars and thirteen stripes original thirteen states of the Union.
Illinois flags for outdoor use are constructed of a durable nylon fabric especially developed for flag use. Nylon's tight weave provides maximum beauty and flyability as well as brilliant, fast colors. Its weave helps shed pollution, dirt and grime that the looser weave alternatives absorb. Nylon is water repellent and mildew resistant.