Among your first stops should be Alton Regional Convention & Visitors Bureau. Here, you'll be able to orient yourself and get some great ideas before you set out exploring.
You're spoiled for sightseeing choice when spending time in Alton. Alton Regional Convention & Visitors Bureau is a good place to start here, but there are plenty of other interesting attractions to consider. Argosy Casino, Fast Eddie's Bon Air, and Robert Wadlow Statue are close to the tourist information center and will top off your day nicely.