During the 1840s and 1850s, wagon trains on the California Trail left the Raft River valley and traveled through the area and over Granite Pass into Nevada.

In 1849, an emigrant party with James Wilkins "encamped at the city of the rocks" on the California Trail just north of the Great Salt Lake Desert.

The area's historical and geological values, scenery, and opportunities for recreation led to its designation as City of Rocks National Reserve in 1988.

The Shoshone and Bannock tribes hunted the buffalo that once roamed in the City of Rocks area and gathered the nuts of the pinyon pine trees.

The arrival of horses in the Americas in the 16th century and swelling European immigration disrupted the Shoshone-Bannock homelands and traditional way of life.

Most emigrants on the California Trail saw no Native Americans, but some of their journals record smoke rising from high hills and the surrounding mountains.

In 1826, Peter Skene Ogden and his Snake River brigade of beaver trappers were the first Euro-Americans to note the City of Rocks.

After many attempts to find a wagon route to California, early California settlers like Joseph B. Chiles and mountain men such as Joseph R. Walker found the route up the Raft River, through the City of Rocks, over Granite Pass and down a series of streams like Goose Creek and Thousand Springs to the Humboldt River.

The City of Rocks and the nearby Granite Pass (Idaho) marked roughly halfway to California for the emigrants and their loaded wagons.

City of Rocks National Reserve was created November 18, 1988 by Public Law 100-696, Arizona-Idaho Conservation Act of 1988.

All lands owned by the United States within the Reserve boundaries were placed under the authority of the National Park Service (NPS).

City of Rocks, an extraordinary encirclement of granite rising out of the gently rolling sagebrush country in south-central Idaho, has attracted and intrigued people since they first entered this region.

One of the reserve's most notable qualities is its large degree of biological diversity concentrated in a relatively small area.

The great variety of textures, colors, and shapes in the natural landscape contributes considerably to the reserve's scenic quality.

However, some of the spires are made of granite that is part of the 2.5 billion-year-old Green Creek Complex that contains some of the oldest rocks in the western United States.

The majority of the soils in the reserve are composed of grus, a coarse angular sand derived from the disintegration of the underlying granitic bedrock.

Climbing on the Twin Sisters, a major geological formation in the Reserve, was banned following a National Park Service decision and later court case involving the Access Fund.