Clarksville is a city in Johnson County, Arkansas, United States. The population was 7,719 at the 2000 census. The city is the county seat of Johnson County.
Clarksville is located at 35°27′50″N 93°28′38″W / 35.46389°N 93.47722°W / 35.46389; -93.47722 (35.464006, -93.477089).
According to the United States Census Bureau, the city has a total area of 18.8 square miles (48.6 km²), of which, 18.0 square miles (46.6 km²) of it is land and 0.8 square miles (2.0 km²) of it (4.10%) is water.