Use of Valles Caldera dates back to the prehistoric times: spear points dating to 11,000 years ago have been discovered. Several Native American tribes frequented the caldera, often seasonally, for hunting and for obsidian, used for spear and arrow points. Obsidian from the caldera was traded by tribes across much of the Southwest. Eventually, Spanish and later Mexican settlers as well as the Navajo and other tribes came to the caldera seasonally for grazing with periodic clashes and raids. Later as the United States acquired New Mexico as part of the Treaty of Guadalupe Hidalgo in 1848, the caldera became the backdrop for the Indian wars with the U.S. Army. Around the same time, the commercial use of the caldera for ranching, and its forest for logging began.