The City of Rocks National Reserve, also known as the Silent City of Rocks, is a United States National Reserve and state park in south-central Idaho, approximately north of the border with Utah. It is widely known for its enormous granite rock formations and excellent rock climbing. The rock spires in the City of Rocks and adjacent Castle Rocks State Park are largely composed of granitic rock of the Oligocene Almo pluton and Archean Green Creek Complex. City of Rocks is also a popular rock climbing area, with over 1,000 traditional and bolt-protected routes. In the 1980s, it was home to some of the most difficult routes in the country, mostly developed by Idaho climber Tony Yaniro. Climbers in the region refer to the area as simply "The City". 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. Names or initials of emigrants written in axle grease are still visible on Register Rock, and ruts from wagon wheels can be seen in some of the rocks. History 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. Signatures in axle grease on rock faces can be seen today. One emigrant saw the distant rocks in August like "water thrown up into the air from numerous artificial hydrants." Beginning in 1843, City of Rocks was a landmark for emigrants on the California Trail and Salt Lake Alternate Trail and later on freight routes and the Kelton, Utah to Boise, Idaho stage route. The area's historical and geological values, scenery, and opportunities for recreation led to its designation as City of Rocks National Reserve in 1988. This unit of the National Park System is managed cooperatively by the National Park Service and the Idaho Department of Parks and Recreation. Native American history 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. They grew to resent the intruders but could do little to stop them. Most emigrants on the California Trail saw no Native Americans, but some