State Route 78 (Arizona–New Mexico) State Route 78 (Arizona–New Mexico) Arizona State Route 78 (SR 78) and New Mexico State Road 78 (NM 78) are a pair of adjoining state highways located in eastern Arizona and western New Mexico linking U.S. Route 191 (US 191) and Arizona State Route 75 near Greenlee County Airport to US 180 northwest of Cliff, New Mexico. It is also known in its Arizona stretch as Mule Creek Road. The western terminus of SR 78 is located at a junction with US 191 and SR 75 at Three Way, Arizona near Greenlee County Airport. The highway heads northeast from this
Arizona State Route 66 Arizona State Route 66 State Route 66 (SR 66) is a surface road in the U.S. state of Arizona in Mohave and Coconino Counties. In 1914, the road was designated "National Old Trails Highway" but in 1926 was re-designated as U.S. Route 66. In 1985, U.S. Route 66 was dropped from the highway system. Parts of the highway were either absorbed into I-40, turned over to the state (SR 66), or turned over to Yavapai County. State Route 66 is a relic of the former U.S. Route 66 in Arizona and is the only part of old US 66 in