Welcome to Calhoun County, Illinois Genealogy and History ~~LOCAL INFO/HISTORY~~ Calhoun County is located on a peninsula between the Mississippi and Illinois Rivers, and its population is 5,191. The county seat is Hardin. Ferries are the major mode of transportation, and the county features many historic sites and nature areas, including the Center for American Archaeology, the Two Rivers National Wildlife Refuge, and the Mississippi River State Fish and Wildlife Area. BACK TO MAIN PAGE ©2007 Genealogy Trails