Wyoming Highway 373

U.S. Route 191
Route information
Auxiliary route of US 91
Length:	1,623.97 mi (2,613.53 km)
Existed:	1926 – present
Major junctions
South end:	SR 80 in Douglas, Ariz.
	I-10 in Willcox, Ariz. I-40 in Sanders, Ariz. I-70 / US-50 in Green River, Utah US-6 in Price, Utah US-40 in Duchesne and Vernal, Utah I-80 / US 30 in Rock Springs, Wyo. US 14 / US 16 / US 20 in Yellowstone Nat'l. Park I‑90 in Bozeman, Mont. US 2 in Malta, Mont.
North end:	Hwy 4 at Canada–US border near Loring, Mont.
Location
States:	Arizona, Utah, Wyoming, Montana
Highway system
United States Numbered Highway System List Special Divided Replaced

U.S. Route 191 (US 191) is a spur of U.S. Route 91 that has two branches. The southern branch runs for 1,465 miles (2,358 km) from Douglas, Arizona on the Mexican border to the southern part of Yellowstone National Park. The northern branch runs for 440 miles (710 km) 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, and one of the longest U.S. three-digit routes.

US 191 begins at the Mexico border in Douglas. US 191 has a ten-mile (16 km) layover with US 70 east of Safford. The route links to State Route 366 (SR 366) and SR 266 to the south of Safford. US 191 intersects Interstate 10 (I-10) in Cochise County. 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 very dangerous mountain road with many sharp curves and little or no shoulders on steep cliffs. North of the byway, the highway is the primary route to access Canyon de Chelly National Monument. US 191 traverses the Navajo Nation before entering Utah.

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Wikipedia