San Augustine County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 7,918. Its county seat is San Augustine.

Texas' 1st congressional district in the United States House of Representatives serves the northeastern portion of the state of Texas. As of the 2000 census, the 1st district contained 651,619 people. It consists largely of three small East Texas metropolitan areas—Texarkana, Texas, Longview–Marshall, and Tyler. With a Cook Partisan Voting Index rating of R+26, it is the most Republican district in Texas. It has been represented by Republican Nathaniel Moran since 2023.