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.

The Saline River is a tributary of the Ohio River, approximately 27 miles (43 km) long, in the Southern Illinois region of the U.S. state of Illinois. The river drains a large section of southeast Illinois, with a drainage basin of 1,762 square miles (4,564 km2). The major tributaries include the South Fork, Middle Fork and North Fork, all lying within the Saline Valley. The once meandering swampy river was important among Native Americans and early settlers as a source of salt from numerous salt springs where it was commercially extracted in the early 19th century.