Carbondale is a city in Jackson County, in the state of Illinois, within the Southern Illinois region. It is located at the junction of Illinois Route 13 and U.S. Route 51, 96 miles (154 km) southeast of St. Louis, Missouri, on the northern edge of the Shawnee National Forest. Carbondale is the home of the main campus of Southern Illinois University. The city is located in Jackson County, Illinois.As of the 2010 census, the city had a population of 25,902, and is the 20th-most populated city outside of the Chicago Metropolitan Area.