U.S. Route 491 (US 491) is a north–south highway running through the Four Corners region of the southwestern United States, specifically traversing New Mexico, Colorado, and Utah. It was formerly known as U.S. Route 666, a designation that sparked public controversy due to its association with the “number of the beast.” In 2003, the highway was officially renumbered to US 491, alleviating concerns and frequent sign thefts.
The route begins in Gallup, New Mexico, at an interchange with Interstate 40, and proceeds northward through remote desert landscapes and Native American tribal lands, including significant stretches within the Navajo Nation. It intersects with U.S. Route 64 in Shiprock, a key regional junction, before continuing into Colorado, where it passes through Cortez. It terminates in Monticello, Utah, where it meets U.S. Route 191.
US 491 serves as a vital corridor for rural communities, tourism, and energy development in the region. Travelers can access notable attractions such as Mesa Verde National Park, the Four Corners Monument, and scenic byways like Trail of the Ancients. Despite its modest length, the route plays a crucial role in connecting culturally rich and geographically diverse parts of the American Southwest.