Red River County is a county in the U.S. state of Texas. As of the 2020 census, its population was 11,587. Its county seat is Clarksville. The county was created in 1835 and organized in 1837. It is named for the Red River, which forms its northern boundary. Red River County was the birthplace of John Nance Garner, 32nd Vice President of the United States.

Clarksville is a city and county seat of Red River County, Texas, United States, in the northernmost part of the Piney Woods region of East Texas. As of the 2020 census, the city population was 2,857.