The California Zephyr is a long-distance passenger train operated by Amtrak between Chicago and the San Francisco Bay Area (at Emeryville), via Omaha, Denver, Salt Lake City, and Reno. At 2,438 miles (3,924 km), it is Amtrak's longest daily route, and second-longest overall after the Texas Eagle's triweekly continuation from San Antonio to Los Angeles, with travel time between the termini taking approximately 521⁄2 hours. Amtrak claims the route as one of its most scenic, with views of the upper Colorado River valley in the Rocky Mountains, and the Sierra Nevada. The modern train is the second iteration of a train named California Zephyr; the original train was privately operated and ran on a different route through Nevada and California.
During fiscal year 2023, the California Zephyr carried 328,458 passengers, an increase of 13.1% over FY2022, but down from its pre-COVID-19 pandemic ridership of 410,844 in FY2019. The train had a total revenue of $51,950,998 in FY2016, the last year that route-specific revenue data was given.