The Illinois Salines, also known as the Saline Springs or Great Salt Springs, is a salt spring site located along the Saline River in Gallatin County, Illinois. The site was a source of salt for Illinois' prehistoric settlers and is now an archaeological site with a large quantity of organic remains. After European settlement of Illinois, the salt springs became part of Illinois' first major industry and were one of the only places in Illinois where slavery was legal after 1818.