Martinsville is a village in Clinton County, Ohio, United States. The population was 440 at the 2000 census. Martinsville is located at 39°19′23″N 83°48′40″W / 39.32306°N 83.81111°W / 39.32306; -83.81111 (39.323042, -83.811003). According to the United States Census Bureau, the village has a total area of 0.4 square miles (1.1 km²), all of it land.