Arizona State Route 64 a route from Williams to the Grand Canyon. In 1935, the highway was extended to the east from the Grand Canyon to US 89. In 1961, the highway was extended further east from US 89 through Tuba City to the New Mexico state line. In 1965, the portion from Teec Nos Pos was renumbered to SR 504 to match New Mexico, which would be renumbered again in 1987 to US 64. In 1965, the section to the east of US 89 became US 164, and would later be renumbered to US 160 in 1969. Arizona State Route 64 State Route
U.S. Route 80 in Arizona was bypassed in 1956 to cross the Colorado River, while the later alignment continued straight ahead into California. Upon crossing the Colorado River to the Fort Yuma Indian Reservation, the older route was still in Arizona. Unlike most of the California and Arizona state border which resides along the Colorado River, the border temporarily cuts north here through the Reservation then east back to the Colorado. This places several acres of land on the western side of the river in Arizona. For a few hundred feet, the state border runs along the western shoulder of pre-1956 US 80. A short