19th century, the town had dirt streets with a large Greek Revival courthouse with Doric columns built by Swiss-born, Evansville, Indiana Architect J. K. Frick & Co in 1861. The courthouse was replaced in 1906 with a larger building designed by then well-known architect John W. Gaddis of Vincennes, Indiana. The structure was an identical model to the Perry County Courthouse at Perryville, Missouri, both built the same year. A smaller version of the central clock tower of the courthouse, including the original clock, manufactured by the Howard Clock Company, of Boston Massachusetts in 1904 was recreated in 1996, and placed in a small lot behind the Clearwave Building's parking lot. The Howard clock company was notable for manufacturing large clocks in such buildings as the Wrigley Building in Chicago, and the Ferry Building in San Francisco, California. The town square was completely surrounded by brick streets in 1906. Harrisburg had of brick streets, but now only a few blocks are left. Harrisburg has not yet begun a National Trust for Historic Preservation, Main Street historical preservation program. Saline County is within a recognized historical district, the "Ohio River Route Where Illinois Began". Two buildings in Harrisburg are currently listed on the National Register of Historic Places, those being the City Hall and the Saline County Poor Farm. The square itself held an array of coal mining offices, privately owned business, grocery and department stores, pharmacies and bars. During the closing of the coal mining era, most of the businesses left the square and moved to the main drag of Rt. 45, constructed in 1926. The courthouse built by John W. Gaddis was replaced with a modern, more efficient building in 1967 after the older building was condemned. Over the years, the architecture that graced Harrisburg square has slowly turned to rotting older structures mixed in with a hodge-podge of newer updated buildings. Currently there are a few privately owned downtown renovation projects in progress on and around the square. The Harrisburg Mitchell-Carnegie Library, located on Church Street south of the square and built with a grant from Andrew Carnegie, was built in 1908 and opened to the public in 1909. The building served the community until 2000 when the library was moved to a new building on north Main Street. During the 1937 flood, the library was used as a makeshift hospital until the water boiler burst. The building