The Christmas Mountains are a small range of mountains next to Big Bend National Park in Brewster County, Texas, United States. The highest peak is 5,728 feet above sea level. The 9,270-acre tract is owned by the Texas State University System and is open to the public and to academic researchers studying the area's natural resources. The area's shallo…The Christmas Mountains are a small range of mountains next to Big Bend National Park in Brewster County, Texas, United States. The highest peak is 5,728 feet above sea level. The 9,270-acre tract is owned by the Texas State University System and is open to the public and to academic researchers studying the area's natural resources. The area's shallow, stony soils support oak, juniper, mesquite, chaparral, various cacti, and grasses.