1. In 1818, Illinois officially became the 21st state in the United States of America. The state was primarily inhabited by Native American tribes such as the Illinois, Kickapoo, Sauk, and Fox, prior to European colonization in the 17th century.

2. In 1954, the Illinois Senate accepted the federal government's offer to build the first section of the interstate highway system in the state. The construction of the system would create numerous jobs and would allow for faster transportation of goods and services.

3. In 1836, the city of Chicago was incorporated as a town. The city's location on Lake Michigan and its connection to other bodies of water made it an important transportation hub and contributed to its early growth as a hub of industry and commerce.

4. In 1868, the first American golf course west of the Allegheny Mountains was established in Downers Grove, Illinois. The nine-hole course was built on the estate of William L. Gregg and was designed by Greg's Scottish gardener, Alex Findlay.

5. In 1904, the St. Louis World's Fair opened to the public. Illinois was heavily involved in the fair, with over 900 exhibits showcasing the state's agricultural and industrial innovations. The Illinois State Building at the fair was designed by Chicago architect James Knox Taylor and was the largest state building in the fairgrounds.