What site became the United States’ first national monument in 1906?

Devils Tower became the United States’ first national monument in 1906.

President Theodore Roosevelt established Devils Tower National Monument by proclamation on September 24, 1906. The dramatic rock formation stands in northeastern Wyoming in the Black Hills region, near the Belle Fourche River.

Devils Tower is a laccolithic formation composed of igneous rock. It rises about 867 feet from its base to its summit and reaches 5,112 feet above sea level. Its distinctive vertical columns made it an early example of a landscape protected for scientific and scenic importance.

The monument designation came shortly after Congress passed the Antiquities Act of 1906, which gave presidents authority to protect historic landmarks, structures, and other objects of scientific interest on federal land. The site is also culturally significant to Indigenous peoples, including the Lakota, who call it Bear Lodge.