Pre-1926 near Monticello|alt=Snow-covered mountains protruding from a plain with tilled soil in the foreground.Before the
Mexican–American War, when this area was ceded to the United States, the main trade route through this part of Mexico was the
Old Spanish Trail. This trail extended from
Santa Fe, New Mexico to Los Angeles. The trail had multiple routes; however, the main route proceeded north towards
Moab, Utah, one of the few places where the
Colorado River can be crossed without having to traverse steep cliffs. The modern US 491 roughly correlates with the main route of the Old Spanish Trail between
Cortez, Colorado and its northern terminus. Before 1926, all of modern US 491 existed as state routes. In New Mexico, US 666 absorbed a portion of
State Road 32 (NM 32) from Gallup to Shiprock, and completely replaced NM 121 from Shiprock to the Colorado state line. The portion in Colorado was numbered State Highway 106 (SH 106) from the New Mexico state line to Cortez, and
SH 10 from Cortez to Utah. At the time, SH 10 traversed the southern portion of Colorado. While most of this corridor today has a U.S. Highway designation, a portion of SH 10 still exists. In Utah, the route was originally numbered
State Route 9 (SR 9), which also included what is now US 191 from Monticello to Crescent Junction. Utah has since re-used the SR 9 designation for a different road.
U.S. Route 666 The route was upgraded to a
U.S. Highway in 1926, as U.S. Route 666. This number was appropriate and in accordance with the road numbering guidelines for U.S. Highways, being the sixth spur along the highway's parent highway, the famed cross-continental highway
U.S. Route 66, from which US 491 breaks around
Gallup, New Mexico. This number was assigned by the
American Association of State Highway Officials (AASHO), a coordinating body that created the U.S. Highway System. Over time the route became known as the "Devil's Highway", a reference to the
Number of the Beast. as well as making the signs targets for
theft. One unnamed highway patrol officer was quoted in
USA Today as stating a drunk-driving suspect told him, "Triple 6 is evil. Everyone dies on that highway." only the New Mexico portion is statistically a dangerous highway. The highway was used as a plot element in films and television, including
Route 666,
Natural Born Killers, These pieces are not accurate in portraying the route; for example, one depicts the route in
Nevada. 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 . The curves force a speed limit of in spots. 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.
Elimination and renumbering of US 666 , a sacred mountain to the Navajo people, is accessed via US 491|alt=Solid rock spire protruding from the desert. In 1985, the US 66 designation was eliminated, leaving US 666 (and other routes) as "orphans". This fact would be used as a supporting factor in later petitions to renumber the highway. In 1992, the part in Arizona was renumbered as an extension of US 191. This truncated US 666 again at Gallup, New Mexico, now at
I-40. Officials in Utah reported that five entire sign assemblies had been cut down with a chainsaw and stolen, while New Mexico officials reported that even signs welded to metal posts, as a theft deterrent, had been stolen. Officials speculated from one scene that someone had intentionally crashed a car into the sign post to break the welds. The dedication of the "new" highway was postponed until July 30, 2003, to coincide with the start of construction projects to improve safety on the highway. At the dedication George Blue Horse, a Navajo medicine man, performed a ceremony to remove the curse from the highway. In the Navajo language he stated, "The road itself never ends. It goes on generation to generation. The new number is a good one. The new road will be a medicine." Construction on the final phase was originally scheduled to begin January 2008, ==Major intersections==