Devil’s Highway

The Mother Road’s 100th birthday offers occasion to remember one of her forgotten children – a scenic Southwestern offshoot with a decidedly devilish moniker: U .S. Highway 666. 

Photos courtesy Douglas C. Towne & Marshall Trimble

Few have greater firsthand knowledge of Route 66 in its glory years after World War II than Arizona state historian Marshall Trimble. He lived along the road dubbed “America’s Main Street” in the northwest Arizona town of Ash Fork from 1947 to 1955. “My mother was a waitress at the 66 Café, my high school basketball jersey was 66, and I worked my way through high school in a Route 66 gas station,” he says.

“I got pretty good at fixing flats, greasing cars and putting snow chains on vehicles in the middle of the night.” 

Trimble remembers Route 66 as a narrow, two-lane ribbon of asphalt that was especially treacherous during heavy snows between Ash Fork and Williams, separated by only 18 miles of road but more than 1,000 feet of elevation. “A Williams girl told me they had to flush their toilets twice – once to get rid of the waste, then a second time to provide drinking water for Ash Fork,” he says.

Route 66 celebrates its 100th anniversary in 2026, and its mystique shows no signs of fading. But this wasn’t the case for one of its tributaries, U.S. Highway 666, which connected many remote Southwestern communities with the Mother Road, including several in eastern Arizona. Some believe the notorious highway number was retired because of sinister events on its dark, demonic pavement, but there might be another reason it was removed from official maps.

 There is no mystery behind the creation of U.S. 666: The road’s nomenclature follows standard highway naming conventions. When the federal government reorganized the informal network of cross-country routes called auto trails in 1926, the American Association of State Highway and Transportation Officials (AASHTO) designated the Chicago-to-Los Angeles route as U.S. Highway 66. Popularly known as Route 66, the east-west highway intersected six major north-south auxiliary roads over its 2,448-mile length, which nourished it with motorists. Travelers from the Great Plains accessed Route 66 via U.S. 166 in Kansas. Those from the Four Corners area used U.S. 666. 

The 141-mile-long spur offered a picturesque drive that started at the Route 66 city of Gallup, New Mexico, and headed north through Navajo Tribal lands before terminating in Cortez, Colorado. 

In 1942, AASHTO extended U.S. 666 south through Arizona to the Mexican border. The new route overlapped Route 66 during its western glide from Gallup to Sanders, Arizona, then continued south through St. Johns and Springerville before entering the White Mountains. South of Alpine, U.S. 666 descended to the copper-mining towns of Clifton and Morenci, then headed west to Safford and south to Willcox before culminating in the border town of Douglas.

Early on, there was little outcry about alleged satanic connections to U.S. 666, even though the Bible calls it the “number of the beast.” Of the 556-mile route, only the stretch from Springerville to Clifton appeared to bedevil drivers, with 460 turns as it dropped 5,500 feet in elevation. “It’s Arizona’s 120-mile rollercoaster,” says Peter Corbett, a former ADOT spokesperson. “Driving it aggressively might shave a few minutes off your trip or many years off your life.” 

Arizona was the first state to renumber U.S. 666, rebranding the stretch from Sanders to Douglas to U.S. 191 in 1992. Corbett doesn’t believe any dark entity was responsible for the change in the numeric designation, at least not directly. “I think ADOT got tired of replacing the U.S. 666 signs along the Devil’s Highway, since vandals were stealing them as demonic souvenirs.”

The road north of Gallup through Colorado to Monticello, Utah, where the northern terminus had been extended in 1970, remained unaffected. But U.S. 666’s days were numbered. Through the 1990s and after, stories of horrifying accidents and supernatural sightings spread online about the remaining section of U.S. 666, including a sinister black vehicle called “Satan’s Sedan” that haunted the highway. Other purported phenomena included UFOs, ghostly hitchhikers, strange fogs, hellhounds with glowing red eyes, bizarre breakdowns and, yes, Satan himself. Tension peaked with the 2001 horror film Route 666, in which zombies attack government agents on the cursed road.

In 2003, New Mexico Governor Bill Richardson asked Colorado and Utah to renumber U.S. 666, arguing that its reputation was hurting nearby residents. Later that year, the last section of the highway from hell was renamed U.S. 491. Highway crews didn’t need to remove any U.S. 666 signs because none remained between Gallup and the Colorado border; they had all been stolen, according to a 2003 New York Times article.

There’s not much demand for the new highway signs, as they are now just nondescript routes in a country filled with roads. Their link to the famed Route 66 has been severed, along with the bragging rights of surviving a trip down the Devil’s Highway. 

Not everyone agrees with the change. “It was a great name that tied in with our Route 66, but a group of busybodies with not enough to do decided there was something evil about the sixes and changed it,” Trimble says. 

Daring Drives

Before folks began getting their “Kicks on Route 66” in 1926, adventurous travelers crossed the country on auto trails, whose charming names disguised poorly marked, inefficient routes over minimally improved roads, including this trio that passed through Arizona. 

Bankhead Highway

This route connected Washington, D.C., and San Diego in 1919. The following year, it was posthumously named after John H. Bankhead, a U.S. Senator from Alabama who was a leader in the early national road-building movement and died in office in 1920. In Arizona, much of the route overlapped with the Old Spanish Trail.

National Old Trails Road

Founded in 1912, the route stretched from Baltimore to Los Angeles, with branches reaching New York City and San Francisco. Its name was derived from combining parts of historical pathways, including the Cumberland Road and the Santa Fe Trail. Much of its route across Arizona was incorporated into Route 66. 

Old Spanish Trail

The route was established in 1915, running from St. Augustine, Florida, to San Diego. It was marked with red, white and yellow signs displaying the “OST” symbol. The road crossed the Colorado River on the Ocean-to-Ocean Bridge, which is still in use in Yuma. Much of the trail later became U.S. Highway 80 in Arizona.