Interstate 40 in Arizona Interstate 40 in Arizona Interstate 40 (I-40) is an east–west Interstate Highway that has a section in the U.S. state of Arizona, connecting sections in California and New Mexico. The section throughout Arizona is also known as the Purple Heart Trail. It enters Arizona from the west at a crossing of the Colorado River southwest of Kingman. It travels eastward across the northern portion of the state connecting the cities of Kingman, Ash Fork, Williams, Flagstaff, Winslow, and Holbrook. I-40 continues into New Mexico, heading to Albuquerque. The highway has major junctions with U.S. Route 93 (US 93) — the
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