U.S. Route 163 (also U.S. Highway 163, US 163) is a U.S. Highway that runs from US 160 northward to US 191 in the U.S. states of Arizona and Utah. The southernmost of its length are within the Navajo Nation. The highway forms part of the Trail of the Ancients, a National Scenic Byway. The highway cuts through the heart of Monument Valley and has been featured in numerous movies and commercials. The highway was designated in 1970, replacing Arizona State Route 464 and Utah State Route 47 as well as a portion of the old alignment of US 160 in Utah. In 1981, US 191 was routed over the northern section of US 163, effectively truncating the northern terminus to Bluff, Utah, from Crescent Junction. The state of Utah briefly had plans for a different routing of US 163 north of Bluff. These plans were rejected, resulting in discrepancies between the signed route and the official designation by the American Association of State Highway and Transportation Officials that were not resolved until 2008. The route number does not follow the numbering convention for U.S. Highways, as the number 163 would normally be used for a spur of US 63; however, these two highways have never connected. Route description Arizona The southern terminus of US 163 is at a junction with US 160 south of Kayenta in Navajo County and Navajo Nation. The road continues to the south of this junction as Bureau of Indian Affairs (BIA) Route 591. US 163 heads north from US 160 to the west of the Kayenta Airport as it passes through the town of Kayenta. The highway curves toward the northeast in Kayenta before it curves back toward the north. As it continues north, the highway goes through an s-curve, resulting in a northeasterly heading. US 163 continues this heading as it heads toward Monument Valley and crosses into Utah. The state of Arizona has designated an stretch of the highway, from approximately north of the US 160 junction to the Utah border, as a scenic route. Utah The Utah portion of the highway begins in Monument Valley, in San Juan County. Just after it enters Utah, the highway junctions with the Monument Valley Visitors center. The highway proceeds northeast until the town of Mexican Hat where the highway both crosses the San Juan River and exits the Navajo Nation. From Mexican Hat, the