Chisos Mountains

The Chisos Mountains, also known as the Chisos, are a mountain range located in the Big Bend area of the Trans-Pecos region of Texas, United States. The mountain system covers 40 square miles and is contained entirely within the boundaries of Big Bend National Park, making it the only mountain range in the United States fully contained within a national park. The Chisos Mountains are the southernmost mountain range in the mainland United States.

The Chisos Mountains were created by volcanic activity during the Eocene Epoch 35-44 million years ago.The highest point in the Chisos Mountain range is Emory Peak at 7,825 ft above sea level.

Source: Wikipedia