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 now one of the most popular whitewater rafting destinations in North America.