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.