High Quality Content by WIKIPEDIA articles! Interstate 40 (I-40) is an east–west Interstate Highway that has a 359.6-mile (578.72 km) section in the U.S. state of Arizona connecting sections in California to New Mexico. 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) in Kingman, the main highway connecting Phoenix and Las Vegas, Nevada, and I-17 in Flagstaff, the Interstate linking Phoenix and Flagstaff.