The California Trail was an emigrant trail of about 1,600 mi (2,600 km) across the western half of the North American continent from Missouri River towns to what is now the state of California. After it was established, the first half of the California Trail followed the same corridor of networked river valley trails as the Oregon Trail and the Mormon Trail, namely the valleys of the Platte, North Platte, and Sweetwater rivers to Wyoming. The trail has several splits and cutoffs for alternative routes around major landforms and to different destinations, with a combined length of over 5,000 mi (8,000 km).

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 2 miles (3.2 km) north of the border with Utah. It is widely known for its enormous granite rock formations and excellent rock climbing.