​ HARRISBURG, a city of Illinois, the county-seat of Saline co. It is on the Cleveland, Cincinnati, Chicago, and St. Louis and the Southern Illinois Railway and Power Company railroads. It is the center of an important agricultural and coal mining region. Its industries include flour mills, wagon shops, saw-mills, etc. It has a library, a post office, and other important public buildings. Pop. (1910) 5,309; (1920) 7,125.