highway travels due east to toward its signed terminus in Bluff. Formerly, the route continued along what is now signed US 191 to I-70, however the portion north of Bluff was not signed after the creation of US 191 and was formally removed in 2008. The length of US 163 in Utah has been designated the Bluff to Monument Valley Scenic byway by the Utah State Legislature and forms part of the Trail of the Ancients National Scenic Byway. All highways in Utah are codified in law; US 163 is defined at Utah Code §72-4-122(3). History The modern routing of US 163 in Utah was initially designated as State Route 47, in 1910. SR 47 extended to Monticello at a junction with then U.S. Route 160. In Arizona, the road appeared on maps as early as 1935, but it was an unimproved dirt road. The Arizona portion was added to the state highway system in 1960 when it was designated as State Route 464. In 1970, US 163 was designated along SR 464 in Arizona and SR 47 in Utah as part of a re-alignment of U.S. highways in the Four Corners region. With the re-alignment, US 160 was re-routed into Arizona instead of Utah. US 163 also absorbed the former route of US 160 to its former terminus at Interstate 70 at Crescent Junction. In 1981, AASHTO approved a new iteration of U.S. Route 191 that absorbed much of the alignment of US 163. Utah truncated US 163 at Bluff. The truncation was made without approval from AASHTO, as the AASHTO logs placed the northern terminus of US 163 at I-70 at Crescent Junction. The state of Utah signed a joint intent with the Navajo Nation and San Juan County in 1986 to construct a new highway to connect Bluff with Montezuma Creek. Businesses in Monument Valley asked the Utah Department of Transportation (UDOT) to request extensions of US 163 and US 666 using this new road. The proposal would have US 163 run from Cedar City to US 160 near Cortez, Colorado along the routes of State Route 14, U.S. Route 89, Arizona State Route 98, U.S. Route 160, the current US 163, the new road from Bluff to Montezuma Creek, and Colorado State Highway 41. The proposal for US 666 would extend to Richfield via upgrades to State Route 95 and State Route 24. UDOT submitted the