Unionville is a city in Putnam County, Missouri, United States. The population was 2,041 at the 2000 census. It is the county seat of Putnam County.
Unionville is located at 40°28′35″N 93°0′22″W / 40.47639°N 93.00611°W / 40.47639; -93.00611 (40.476421, -93.006005).
According to the United States Census Bureau, the city has a total area of 2.0 square miles (5.2 km²), all of it land.