Clarksville is a city in Red River County, Texas, in the United States. As of the 2000 census, the city population was 3,883. It is the county seat of Red River County.
Clarksville is located at 33°36′40″N 95°3′9″W / 33.61111°N 95.0525°W / 33.61111; -95.0525 (33.611086, -95.052448).
According to the United States Census Bureau, the city has a total area of 3.0 square miles (7.7 km²), all of it land.