U.S. Route 191 (US 191) is a north–south U.S. Highway in eastern Arizona. The highway runs for , making it Arizona's longest numbered highway. The highway begins at State Route 80 near Douglas and crosses over the Utah state line near Mexican Water in the Navajo Nation. Between Douglas and Utah, US 191 shares multiple concurrencies with I-10, US 70, US 180, US 60, SR 61, I-40, SR 264, and US 160.
Until 1981, the route taken by US 191 between I-40 in Chambers and the Utah state line was designated as SR 63. The route from SR 80 in Douglas to I-40 in Sanders was originally designated as part of US 666. US 666 was often associated with the biblical devil, due to the number 666 occasionally being considered the "number of the beast." The highway number caused discomfort with the general public and led to the constant sign theft of US 666 markers along the highway, prompting the redesignation of US 666 as a section of US 191 in 1992.
Route description
With a total length of , the section of U.S. Route 191 (US 191) through Arizona has the longest distance of any numbered highway within the state. US 191 almost traverses the entire length of Arizona, but just short of the Mexican border at SR 80 near Douglas. However, the route is connected to the border via SR 80 and US 191 Business (which has no direct connection to US 191 proper). Large sections of the serpentine route taken by US 191 are indirect and include switchbacks in the mountainous regions near Alpine. Part of US 191 is designated as the Coronado Trail Scenic Byway, between Clifton and Springerville.
Douglas to Safford
The national southern terminus of US 191 is located at an intersection with SR 80 west of Douglas, in Cochise County. It heads north from this junction, past Bisbee Douglas International Airport and then through the unincorporated communities of McNeal and Elfrida before passing by Sunizona and the western terminus of SR 181, which provides access to Chiricahua National Monument. The road curves west and heads toward Sunsites, where it turns to the northwest and passes by the community of Cochise with a bridge over the Union Pacific Railroad. Continuing northwest, US 191 meets Interstate 10 at Exit 331, a trumpet interchange, and has a concurrency with I-10 for about . Heading northeast, I-10/US 191 passes around Willcox, with three exits serving the town: Exit 336, which is the southwestern end of the Willcox I-10 Business Loop; Exit 340, which is the northern terminus of SR 186; and Exit 344, which serves as the north end of the Business Loop.
Northeast of Willcox, US 191 leaves I-10 at Exit 352 and heads north toward Safford, leaving Cochise County and entering Graham County along the way. Just north of I-10, US 191 passes through an intersection with Page Ranch Road, officially designated as US 191 Wye. This provides a shortcut for traveling between Bowie and Safford, as the mainline of US 191 is curved toward the west near I-10. Going toward Safford, the eastern terminus of two state routes intersect the route, namely SR 266, which provides access to Fort Grant, and SR 366 in Swift Trail Junction, which climbs up to the summit of Mount Graham and provides access to Mount Graham International Observatory. Arriving in Safford, US 191 turns east at an intersection with 5th Street (US 70), where a concurrency with US 70 begins.
Safford to St. Johns
Traveling east from Safford, US 70/US 191 passes by the communities of Solomon and San Jose before US 191 turns northeast to split from US 70. The route crosses the Gila River, then heads toward Three Way, passing through the Black Hills and entering Greenlee County. At Three Way, US 191 turns to the north, but the intersection is the northern terminus of SR 75, which heads toward Duncan, and the western terminus of SR 78, which heads into New Mexico toward Mule Creek. Heading north, US 191 is a divided highway for about until it arrives in Clifton, the start of the road's designation as the Coronado Trail Scenic Road (both an Arizona Scenic Route and a National Scenic Byway). This scenic road approximates the route Francisco Vázquez de Coronado took between 1540 and 1542. At the intersection with Zorrilla Street in Clifton, the US 191 designation temporarily ends and the road continues as US 191 Temporary through the Morenci mine.