Big Sandy is a town in Upshur County, Texas, United States. As of the 2020 census, the town's population was 1,231. A lake of the same name is cut nearly in half by U.S. Highway 80, the main thoroughfare of Big Sandy. It lies directly west of the larger cities of Gladewater and Longview.

Upshur County is a county located in the eastern part of the U.S. state of Texas. As of the 2020 census, the population was 40,892. The county seat is Gilmer. The county is named for Abel P. Upshur, who was U.S. Secretary of State during President John Tyler's administration.