Brewster County is a county located in the U.S. state of Texas. It is in West Texas and its county seat is Alpine. It is one of the nine counties that comprise the Trans-Pecos region, and borders Mexico. Brewster County is the largest county by area in the state- at 6,192 square miles it is over three times the size of the state of Delaware, and more than 500 square miles bigger than Connecticut. As of the 2020 census, the population was 9,546.