President Theodore Roosevelt established Devils Tower National Monument on September 24, 1906. This spectacular rock formation rises 1,253 feet (382 m) above the nearby Belle Fouche River. The monument attracts both visitors and climbers from around the world. American Indians consider the area sacred, a place for prayer and renewal. Their prayer bundles and cloths can be seen tucked into rock crevices.
Devils Tower is a steep-sided igneous body and possibly a remnant of a volcanic neck. It is made of magma that solidified at a shallow level below the surface and created columnar joints. When this igneous rock cooled, the rock developed shrinkage fractures, producing elongated pillarlike columns. Erosion and frost wedging striped the outlying layers of rock away and formed a huge tallis slope around the base of the monolith. The rolling hills of this South Dakota 1,347 acre park are covered with pine forests, deciduous woodlands, and prairie grasslands. Deer, pronghorn, prairie dogs, and other wildlife are abundant and provide another element of interest.