The California Zephyr is a passenger train operated by Amtrak between Chicago, Illinois, and Emeryville, California, passing through the states of Illinois, Iowa, Nebraska, Colorado, Utah, Nevada, and California. At 2,438 miles (3,924 km) it is Amtrak's longest route and is also one of the most scenic, with views of the upper Colorado River valley in the Rocky Mountains, and the Sierra Nevada.