St. Clair County Historical Society was founded in 1905 and continues today promoting the study and dissemination of local and general historical information. The Society encourages research and preservation of St. Clair County history.

The St. Clair County Historical Society is one of the oldest county societies in Illinois. The Society operates historic museums, the Victorian Home-Museum, a Greek Revival home built in 1866, and the Emma Kunz Home Museum, a classic example of the German street house circa 1830.

Holdings chiefly relate to St. Clair County and Belleville in particular. Some of the more important groups of material include St. Clair County atlases, (1874-1927), and the oldest land ownership map of the area, (1863); Scott Air Force Base complete written and pictorial history, (1914-1950); Illinois Historical collections, (1778-1826), 3 linear feet; City of Belleville Directories, (1868-1968); area family histories, (late 1800's- ); and the Memoirs of Gustave Koerner, (1709-1896), 2 volumes, which focus upon the German settlements in the St. Clair County area.