Harrisburg is located in southern Illinois in central Saline County
(of which it is the county seat) only minutes north of the Shawnee National Forest
and 25 miles west of the Ohio River
at the intersection of U.S. Highway 45 and SR 34/145. The population estimate for 2000 was about 9,900.
The area is an outdoor enthusiast's joy, featuring the 3,300-acre Garden of the Gods Recreation Area with its scenic limestone bluffs, Pounds Hollow Recreation Area with Ox-Lot Cove and the Rim Rock National Recreational Trail.
Harrisburg is home to Southeastern Illinois College, a community college offering its educational facilities to county residents.