Putnam County is in north central Missouri. At the 2020 census, the population was 4,681. Its county seat is Unionville. The county was organized February 28, 1845, and named for Israel Putnam, a hero in the French and Indian War and a general in the American Revolutionary War.

Unionville is a city in Putnam County, Missouri, United States. The population was 1,735 at the 2020 census. It is the county seat of Putnam County.