Upcoming free hours for Illinois residents include:Third Thursdays, 5:00–8:00, beginning April 16, 2026Free Summer Thursdays, 5:00–8:00, June 11–September 17, 2026You can reserve your free tickets online in advance; your resident status will be verified using the zip code associated with the billing address provided.If you’re unable to reserve tickets in advance, please stop by the admissions desk