Callaway County is a county located in the U.S. state of Missouri. As of the 2010 U.S. Census, the county's population was 44,332. Its county seat is Fulton. The county was organized November 25, 1820, and named for Captain James Callaway, grandson of Daniel Boone. Callaway County is also referred to as "The Kingdom of Callaway" after an incident in which residents confronted Union troops during the U.S.