There are 1 US Post Offices in Terrell County serving a total of 927 residents equating to 927 residents per post office. It's estimated that approximately 1,480 packages are handled across the 1 county post offices annually. Terrell County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 984, making it the eighth-least populous county in Texas. Its county seat is Sanderson. The county was named for Alexander W. Terrell, a Texas state senator. Terrell County is one of the nine counties that comprise the Trans-Pecos region of West Texas. It is the setting for Cormac McCarthy's novel No Country for Old Men, and the Academy Award-winning film adaptation of the same name."