U.S. Route 191 (US 191) is a spur of U.S. Route 91 that has two branches. The southern branch runs for from Douglas, Arizona on the Mexican border to the southern part of Yellowstone National Park. The northern branch runs for from the northern part of Yellowstone National Park to Loring, Montana, at the Canada–US border. Unnumbered roads within Yellowstone National Park connect the two branches. The highway passes through the states of Arizona, Utah, Wyoming, and Montana. The highway was designated in 1926 and its routing has changed drastically through the years. The modern US 191 bears almost no resemblance to the original route, which was primarily in the state of Idaho. Most of the current route of US 191 was formed in 1981. Since the extensions in the 1980s and 1990s, U.S. Route 191 is much longer than its parent route to which it no longer connects, and it is one of the longest U.S. three-digit routes. Route description |- |AZ | |- |UT | |- |WY | |- |MT | |-class="sortbottom" |Total | |- |} Arizona US 191 begins in Cochise County, Arizona at a signaled intersection with Arizona State Route 80 (SR 80) and Historic U.S. Route 80 (Historic US 80) near Douglas. The highway then proceeds north past Bisbee Douglas International Airport passing through the hamlets of Elfrida and McNeal. Near Sunizona, US 191 intersects with the western terminus of SR 181. US 191 then curves west for before turning northwest through Sunsites and Cochise. US 191 intersects Interstate 10 (I-10) near Cochise at a trumpet interchange (I-10 Exit 331). US 191 and I-10 run concurrent for around Willcox. In Willcox, I-10/US 191 serves as the northern terminus for SR 186 at Exit 340. The city itself is served by the Willcox I-10 Business Loop, which begins and ends at I-10/US 191 southwest and northeast of the city. In Bowie Junction at Exit 352, US 191 leaves I-10 and heads north, exiting Cochise County and entering Graham County. US 191 has a overlay with US 70 east of Safford. The route links to State Route 366 (SR 366) and SR 266 to the south of Safford. The route between Springerville and Morenci was designated a National Scenic Byway and given the name of Coronado Trail Scenic Byway, as this approximates the path taken by Francisco Vásquez de Coronado between 1540 and 1542. This is a