El Capitan, the southern end of the Guadalupe range in far West Texas, rises 8,085 feet and is the seventh-highest peak in the state. A prominent Trans-Pecos landmark above U.S. 62/180, it is an exposed remnant of the ancient Capitan Reef, formed about 290 million years ago beneath an inland sea and later uplifted and eroded into its present limestone mass. Although nearby water sources drew earlier human use, the mountain became important after the United States took control of the region as a landmark on the Guadalupe Pass route. It also stood near the disputed salt flats and later became a celebrated feature of Guadalupe Mountains National Park, opened in 1972.