Callaway County is a county located in the U.S. state of Missouri. As of the 2020 United States Census, the county's population was 44,283. Its county seat is Fulton. With a border formed by the Missouri River, the county was organized November 25, 1820, and named for Captain James Callaway, grandson of Daniel Boone. The county has been historically referred to as "The Kingdom of Callaway" after an incident in which some residents confronted Union troops during the U.S. Civil War.

Fulton is the largest city in and the county seat of Callaway County, Missouri, United States. Located about 22 miles (35 km) northeast of Jefferson City and the Missouri River and 20 miles (32 km) east of Columbia, the city is part of the Jefferson City, Missouri, Metropolitan Statistical Area. The population was 12,600 at the 2020 census. The city is home to two universities, Westminster College and William Woods University; the Missouri School for the Deaf; the Fulton State Hospital; and the Fulton Reception and Diagnostic Center state prison. Missouri's only nuclear power plant, the Callaway Plant is located 13 miles southeast of Fulton.