The U.S. Highways in Utah are maintained by the Utah Department of Transportation (UDOT). The United States Numbered Highway System is a nationwide system with only a small portion of its routes entering Utah. Originally, the State Road Commission of Utah, created on March 23, 1909, was responsible for maintenance, but these duties were rolled into the new UDOT in 1975.^[1] There are 2,061.979 miles (3,318.434 km) of U.S. Highways in the state. The longest is U.S. Route 89 at 502.577 miles (808.819 km) and the shortest is U.S. Route 89A at 2.94 miles (4.73 km). Six former U.S. Highways exist in the state of Utah; of these, five have been replaced by current interstate and U.S. Highways, while the other was replaced by a state route. The most recent change was the redesignation of U.S. Route 666 as U.S. Route 491 in 2003.^[2]

Mainline routes

Number	Length (mi)	Length (km)	Southern or western terminus	Northern or eastern terminus	Formed	Removed	Notes
US 6	373.963	601.835	US 6 / US 50 at the Nevada state line towards Ely	I-70 / US 6 / US 50 at the Colorado state line towards Grand Junction	01936-01-011936	current	US 6 enters Utah through Delta, joined with US 50 until just after Delta and crosses across the middle of the state before joining I-70 and US 50 again to enter into Colorado, east of Cisco.[3][4]
US 30S	—	—	Idaho state line near Snowville	Wyoming state line towards Evanston	01926-01-011926	01970-01-01c. 1970	Replaced by I-80 / I-84 / US 189[5]
US 40	174.624	281.030	I-80 at Silver Creek Junction near Park City	US 40 at the Colorado state line towards Dinosaur	01926-01-011926	current	US 40 starts at I-80 outside of Park City and heads through Heber City and Duchense before passing into Colorado near the Dinosaur National Monument.[6][7]
US 50	334.920	539.001	US 6 / US 50 at the Nevada state line towards Ely	I-70 / US 6 / US 50 at the Colorado state line towards Grand Junction	01926-01-011926	current	US 50 enters Utah joined with US 6 until just outside Delta, crossing the midsection of Utah, before joining with I-70 for its final 174 miles (280 km) to Colorado.[8][9]
US 89	502.577	808.819	US 89 at the Arizona state line towards Page	US 89 at the Idaho state line at Bear Lake	01926-01-011926	current	US 89 is the longest U.S. Highway in Utah, going from the Arizona border to Idaho, paralleling I-15 for a good majority of the route, but it does split off at the north and south end of the route.[10][11]
US 91	45.271	72.857	I-15 south of Brigham City	US 91 at the Idaho state line towards Preston	01926-01-011926	current	The highway currently serves as a connection between the Cache Valley area of Utah and Idaho to the Salt Lake and Pocatello population centers.[12][13]
US 160	—	—	US 6 / US 50 at Crescent Junction	Colorado state line near Monticello	—	01970-01-011970	Replaced by US 163/US 666 (modern US 191 and US 491)[14]
US 163	41.405	66.635	US 163 at the Arizona state line in Monument Valley	US 191 at Bluff	01970-01-011970	current	US 163 enters Utah in Monument Valley in the southeastern part of the state, across the San Juan River towards Bluff.[15][16]
US 189	29.216	47.019	I-15 south of Provo	I-80 / US 189 at the Wyoming state line towards Evanston	01938-01-011938	current	From I-15 in Provo northeast through Provo Canyon to Heber City. From this point it overlaps US 40 until it intersects I-80, at which point it overlaps I-80 until the Wyoming border near Evanston.[17][18]
US 189	—	—	US 91 in Nephi	US 89 at Pigeon Hollow Junction	—	01938-01-011938	Replaced by SR-132[19]
US 191	404.168	650.445	US 191 at the Arizona state line towards Ganado	US 191 at the Wyoming state line towards Rock Springs	01981-01-011981	current	US 191 enters Utah in the southeastern part of the state and travels northward through Moab, veers to the northwest to Price, and back to the northeast through Vernal, before exiting into Wyoming near Flaming Gorge Reservoir.[20][21]
US 450	—	—	US 6 / US 50 at Crescent Junction	Colorado state line near Monticello	01926-01-011926	—	Replaced by US 160 (modern US 191 and US 491)[22]
US 491	17.020	27.391	US 191 in Monticello	US 491 at the Colorado state line towards Dove Creek	02003-01-012003	current	From US 191 in Monticello eastward until it exits the state into Colorado.[23][24]
US 530	—	—	US 40 near Park City	US 30S near Echo	01926-01-011926	—	Replaced by US 189 (modern I-80)[22]
US 666	—	—	US 191 in Monticello	US 666 at the Colorado state line towards Dove Creek	01970-01-011970	02003-01-012003	Replaced by US 491[2]
Former

• 
  US 50 descending from Skull Rock Pass in western Utah
• 
  US 89 near Long Valley Junction, a Utah Scenic Byway

Special routes

Number	Length (mi)	Length (km)	Southern or western terminus	Northern or eastern terminus	Formed	Removed	Notes
US 6 Bus.	3.43	5.52	US 6/US 191 in Helper	US 6/US 191 in Spring Glenn (south of Helper)	01953-01-011953	current	Serves Helper, former US 6 through downtown. Currently co-signed US 191 Business. Was previously cosigned US 50 Business
US 6 Bus.	2.942	4.735	US 6/US 191 in Price	US 6/US 191 in Price	01975-01-011975	current	Cosigned SR-55; former routing of US 6/50
US 40 Alt.	—	—	State Street	mouth of Parley's Canyon	01964-01-011964	01974-01-011974	Served Salt Lake City along modern SR 186/Foothill Blvd. Was signed US 40 ALt in 1964, signed mainline US 40 in 1965, reverted back to Alternate in the 1970s.
US 40 Alt.	—	—	Kimball Junction	east of Park City	01953-01-011953	01969-01-011969	Served Park City
US 50 Alt.	—	—	Ely, Nevada	Provo	01954-01-011954	01976-01-011976	Former mainline US 50. Utah portion was entirely concurrent with other US Routes except for the portion that is modern SR 201. Most of the Nevada portion is today US 93 ALT/US 93.
Temp. US 50	—	—	Colton, Utah	Castle Gate	01912-01-011912[25][26]	01927-01-011927	Exited the Price River Canyon along modern US 191 near Castle Gate and returned via Emma Park Road to bypass a narrow, meandering portion of the canyon.
US 89A	2.94	4.73	US 89A at the Arizona state line towards Fredonia	US 89 in Kanab	01960-01-011960	current	Original routing of US 89 prior to the construction of the Glen Canyon Dam; demoted to an auxiliary route listed as SR-11 until 2008; provides access to Grand Canyon National Park from Utah[10][27]
US 89A	—	—	Corner of 300 West and North Temple st in Salt Lake City	South Salt Lake	—	—	Routed along 300 West in Salt Lake City. Co-signed US 91 ALT
US 89A	—	—	North Salt Lake	Farmington	01930-01-01c. 1930	—	Former US 89/91, Modern SR 106
US 91 Alt.	—	—	Corner of 300 West and North Temple St in Salt Lake City	South Salt Lake	—	—	Cosigned US 89 ALT, along 300 West in Salt Lake City
US 91 Alt.	—	—	North Salt Lake	Farmington	01930-01-01c. 1930	—	Cosigned with US 89 ALT, modern SR 106
US 91 Alt.	—	—	Layton	Ogden	—	—	Former US 91, modern SR 26, SR 126 and briefly SR 273
US 189 Alt.	—	—	Hailstone	Wanship	—	—	Modern SR 32. Modern SR 32 has alternated designations between US 189 and US 189ALT.
US 191 Bus.	3.43	5.52	US 6/US 191 in Helper	US 6/US 191 in Spring Glenn (south of Helper)	01981-01-011981	current	Serves Helper Cosigned US 6 Business, former mainline US 6/50
Former