Topography The Big Bend region consists of a generally level plain, punctuated by mountains. The plain starts at some 2000 feet above sea level in the lower regions of the natiounal park, to 4,500 feet or so at the northern end. This plain is part of the Chihuahuan desert, which extends well down into Mexico.

The plain is dotted with mountain peaks of volcanic origin. From almost any point in the area, one or more of these peaks are visible. However, there are two areas where peaks are concentrated. One is the Chisos Mountains approximately in the center of the National Park, and the other is the Davis Mountains, near the town of Ft. Davis.

The Chisos mountains rise spectacularly out of the level desert. There are several peaks arranged in a rough circle, topped by Emory Peak at 7,825 feet, which is the 10th highest peak in Texas. In between these peaks is a depression, called "the Basin", which is about a mile in diameter. The altitude of the basin is about 5000 feet. The Basin is drained by a single stream, through a slot in the surrounding mountains called "the Window".

The Davis Mountains consist of a group of several peaks rather close together, topped by Mt. Livermore, at 8,378 ft, the fifth highest in Texas. Also in the Davis Mountains is the McDonald Observatory of the University of Texas. It is located on Mt. Locke, 6,791 ft.