[2] The Arizona State Highway Department (ASHD) formally recognized the U.S.

Highways within Arizona were first being planned, the proposed routes consisted of U.S. Route 60 (US 60) from Topock to Lupton, US 70 from Holbrook to New Mexico, US 80 from Yuma to New Mexico, US 89 from Flagstaff to Utah, US 91 from Nevada to Utah through the Arizona Strip, US 180 from Florence Junction to New Mexico, US 280 from Ash Fork to Phoenix and US 380 from Tucson to Nogales.

US 60 had also been established over other existing state highways from Ehrenberg to Springerville, creating a concurrency with US 80 and US 89 between Phoenix and Florence Junction.

US 666 was concurrent with US 66 between Lupton and Sanders, US 260 from St. Johns to Alpine and US 70 between San Jose and Safford.

In 1959, US 89 between Utah and Bitter Springs was moved onto a new route through Page over the Glen Canyon Dam.

[14] In 1960, the southern section of SR 95 between Quartzsite and San Luis was re-designated as an extension of US 95.

[17] US 93 was also extended southeast from US 66 in Kingman to a junction with US 89 near Wickenburg, replacing part of SR 93.

[20] US 163 was also established in the Navajo Nation, starting at US 160 near Kayenta and going through Monument Valley into Utah.

[20] Before US 163 was established, the route was designated as SR 464[21] In 1974, US 91 was entirely decommissioned south of Brigham City, Utah.

[13] However, the section between Gila Bend and Buckeye replaced by a northern extension of SR 85.

[24] In 1979, the American Association of State Highway and Transportation Officials (AASHTO) approved a request from California and Arizona to truncate US 66 from the California state line, east to I-40 and US 666 in Sanders.

In 1981, SR 63 was decommissioned after it and BIA Route 12 became a southern extension of US 191 across the Utah state line into Arizona near Mexican Water, ending at US 66/I-40 in Chambers.

[30] AASHTO recognized and approved the elimination of US 66 in 1985, with the entire route also being removed nationwide.

Highways recognized by the ADOT Parkways, Historic and Scenic Roads Program.