1. Illinois became a state: On September 1, 1818, Illinois became the 21st state in the United States. Prior to its statehood, Illinois was a part of the Northwest Territory and later the Illinois Territory.

2. Lincoln-Douglas Debate: On September 1, 1858, the first of the famous Lincoln-Douglas Debates took place in Ottawa, Illinois. The debates were a series of seven debates between Republican Abraham Lincoln and Democrat Stephen A. Douglas in the campaign for the United States Senate seat from Illinois.

3. Chicago World's Fair: On September 1, 1893, the World's Columbian Exposition opened in Chicago, Illinois. The fair celebrated the 400th anniversary of Christopher Columbus's arrival in America and attracted millions of visitors from around the world.

4. Illinois Central Railroad Strike: On September 1, 1911, the Illinois Central Railroad workers went on strike, demanding better working conditions and higher wages. The strike lasted for several months and resulted in violence between the strikers and the National Guard.

5. Illinois 54th Infantry Regiment: On September 1, 1944, the Illinois 54th Infantry Regiment became the first African American regiment to fight in World War II. The regiment was a part of the U.S. Army's 92nd Infantry Division and fought in Italy.