Clarksville is a city and county seat of Red River County, Texas, in the United States in the northernmost part of the Piney Woods region of East Texas.
Clarksville is located at 33°36′40″N 95°3′9″W (33.611086, -95.052448). Located 58 miles (93 km) northwest of Texarkana near the center of the county, it is at the junctions of U.S. Highway 82, State Highway 37, and Farm roads 114, 412, 909, 910, and 1159.