The South Fork American River is a major tributary of the American River in El Dorado County, California, draining a watershed on the western slope of the Sierra Nevada east of Sacramento. The river begins in pristine Desolation Wilderness and flows through the Sierra Nevada foothills. The river at Coloma was the site of James Marshall's discovery of gold at Sutter's Mill on January 24, 1848, which started the California Gold Rush. The South Fork of the American is "the most popular recreation stream in the West" for whitewater rafting in North America, e.g., 80,000 visitors in 2011. Professional whitewater rafting companies have been offering commercial rafting trips on the South Fork American River since 1978.

Lake Tahoe is a freshwater lake in the Sierra Nevada of the Western United States, straddling the border between California and Nevada. Lying at 6,225 ft (1,897 m) above sea level, Lake Tahoe is the largest alpine lake in North America, and at 122,160,280 acre⋅ft (150.7 km3) it trails only the five Great Lakes as the largest by volume in the United States. Its depth is 1,645 ft (501 m), making it the second deepest in the United States after Crater Lake in Oregon.