The longest continuous train ride in the United States is Amtrak’s California Zephyr, which covers a staggering 2,438 miles (3,924 km). This iconic journey runs from Chicago, Illinois, to Emeryville, California (just outside San Francisco). The trip takes approximately 51 to 52 hours to complete, spanning three days and two nights. Passengers travel through some of the most spectacular scenery in North America, including the Nebraska plains, the heart of the Rocky Mountains, the red rock deserts of Utah, and the snow-capped Sierra Nevadas. While the Texas Eagle combined with the Sunset Limited can technically cover more mileage (over 2,700 miles) if you book them as a through-service from Chicago to Los Angeles, the California Zephyr remains the definitive single-route transcontinental experience. For the best views, travelers typically head to the "Sightseer Lounge" car, which features floor-to-ceiling windows. Booking a "Roomette" or "Bedroom" is highly recommended for this journey, as it includes all meals in the Dining Car and provides a private space to sleep during the two-night trek across the continent.