Interstate 10 in Arizona 2013. The remainder of the old US 80 section was rebuilt to interstate standards, with completion in 2014. East of Tucson, I‑10 parallels and in some cases overlies old US 80 to Benson, and was originally co-signed as US 80 and SR 86. The section of I-10 from Valencia Road to Rita Road was the first construction project in the state of Arizona funded by the Federal Aid Highway Act of 1956. Construction began in 1957 and was completed in 1960. From Benson, the Interstate follows the Southern Pacific mainline east through Willcox and Bowie to New Mexico, rather than
Arizona State Route 366 Arizona State Route 366 State Route 366 (SR 366) is a highway in Graham County, Arizona that runs from its junction with US 191 south of Safford to near the summit of Mount Graham. It is a winding mountain road with one half primarily a northwest-southeast route, the other half being northeast-southwest. SR 366 is a highway that connects Mount Graham with US 191 (originally US 666) at Swift Trail Junction south of Safford. The western terminus of the highway is located near a ranger station near the peak of Mount Graham. The highway heads in a southeastern route as