page_title: U.S. Route 491
section_title: Extensions into Arizona and Utah
hierarchical_section_title: U.S. Route 491 / History / Extensions into Arizona and Utah
context_page_description: U.S. Route 491 is a north–south U.S. Highway serving the Four Corners region of the United States. One of the newest designations in the U.S. Highway System, it was created in 2003 as a renumbering of U.S. Route 666. With the 666 designation, this road was nicknamed the "Devil's Highway" because of the significance of the number 666 to many Christian denominations, which believe it to be the Number of the Beast. This Satanic connotation, combined with a high fatality rate along the New Mexico portion, convinced some people the highway was cursed. The problem was compounded by persistent sign theft. These factors led to two efforts to renumber the highway, first by officials in Arizona, later in New Mexico. There have been safety improvement projects in recent years, and fatality rates have subsequently decreased.
  The highway, now a spur route of US 91 via its connection to US 191, runs through Colorado, New Mexico, and Utah, as well as the tribal nations of the Navajo Nation and Ute Mountain Ute Tribe. The highway passes by two mountains considered sacred by Native Americans: Ute Mountain and an extinct volcanic core named Shiprock.
context_section_description: By 1942, the southern terminus of the route was extended to Douglas, Arizona, at the Mexican border.  It ran concurrent with US 66 for 30 miles (48.3 km) before the turn south. The Arizona portion of the highway is known as the Coronado Trail Scenic Byway, as it approximated the path of the Spanish explorer, Francisco Vásquez de Coronado. This portion is noted for mountainous terrain, with hairpin turns and steep grades, that reaches an altitude of over 9,000 feet (2,700 m). The curves force a speed limit of 10 miles per hour (16 km/h) in spots.
  In 1970, several U.S. Highways in the Four Corners region were re-aligned. As part of this change, US 160 was rerouted west of Cortez to serve the Four Corners Monument and enter Arizona instead of Utah.  US 666 was extended up part of the old route of US 160 to Monticello, Utah, at an intersection with then US 163 (now US 191).
  In 1985, the Utah Department of Transportation petitioned to extend US 666 northwest to Richfield, but the proposal was rejected. The proposed extension followed SR 95, SR 24, and SR 119. A concurrency with US 191 would have been routed through Blanding and Monticello to connect to the rest of the route. One of the reasons cited for rejecting the proposal was that portions of SR 24 were not built to standards desired for additions to the U.S. Highway System.
caption: Directional colored shields found on US 666 in Arizona during the 1950s