The Illinois Monument is a public monument located in the Kennesaw Mountain National Battlefield Park in Cobb County, Georgia, United States. The monument honors the soldiers from Illinois who fought in the Battle of Kennesaw Mountain during the Atlanta campaign of the American Civil War. It is located on Cheatham Hill, the site of intense fighting during the battle, and was dedicated in 1914, on the 50th anniversary of the battle. It was designed by Mario Korbel and James Dibelka.

Kennesaw Battlefield Park preserves a Civil War battleground of the Atlanta Campaign, and also contains Kennesaw Mountain. It is located at 900 Kennesaw Mountain Drive, between Marietta and Kennesaw, Georgia. The name "Kennesaw" derives from the Cherokee Indian "Gah-nee-sah" meaning "cemetery" or burial ground. The area was designated as a U.S. historic district on October 15, 1966.