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 (16,040 km2) it is over three times the size of the state of Delaware, and more than 500 square miles (1,300 km2) bigger than Connecticut.

West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the arid and semiarid lands west of a line drawn between the cities of Wichita Falls, Abilene, and Del Rio.