Tule Mountain is a 3,825-foot summit in Brewster County, Texas, within Big Bend National Park, rising in the Chisos Mountains of the hot, arid Chihuahuan Desert. Its slopes support live oak, piñon pine, juniper, and grasses. The mountain rises about 1,200 feet above Alamo Creek over 1.5 miles, and runoff from the peak drains into that tributary of the Rio Grande. Geologically, it consists of volcanic rock formed about 33 to 42 million years ago in the late Eocene, with exposed layers including Chisos tuffs, Ash Spring Basalt, conglomerates, Mule Ear Spring Tuff, and a trachyandesite cap dated to 33 million years ago.