Devils Tower was the first U.S. national monument, proclaimed by President Theodore Roosevelt in 1906.
Roosevelt established Devils Tower National Monument in Wyoming on September 24, 1906, using authority granted by the Antiquities Act. The law allowed presidents to protect “objects of historic or scientific interest” on federal land without waiting for Congress to create a national park.
Devils Tower is a striking geological formation rising about 867 feet above the surrounding landscape. Geologists generally describe it as the eroded remnant of an igneous intrusion, although the exact underground origin has been debated. The site is culturally important to many Indigenous nations, including the Lakota, who have traditional stories connected with the formation.
The monument is often confused with Yellowstone, which became the world’s first national park in 1872. A national monument and a national park are different designations, although both protect significant places. Devils Tower’s 1906 proclamation made it the first site in the national-monument system.