The first highway designated between
Gila Bend and
Tucson was the Lone Star Trail in 1925. This late
auto trail utilized a route through
Maricopa alongside the
Southern Pacific Railroad between
Gila Bend and
Casa Grande. Part of the Lone Star Trail was designated as Arizona State Route 84 by the
Arizona State Highway Department on September 9, 1927. Originally, SR 84 terminated at
US 80 in Tucson in the east and
SR 187 in Casa Grande in the west. In 1928, the western terminus of SR 84 was extended to US 80 in Gila Bend. Unlike the Lone Star Trail, SR 84 took a more direct route through the mountains south of Maricopa to reach Gila Bend. This westward extension allowed SR 84 to become a shortcut for
US 80 traffic to bypass
Phoenix while heading to and from
San Diego, California. Starting in 1930, SR 84 also made up the Casa Grande to Tucson segment of the Broadway of America transcontinental highway, with
SR 87 and US 80 forming the remainder of the route through Arizona. By 1935, all of SR 84 was paved. . In 1936, real estate developer Stanley Williamson proposed the idea of developing segments of Casa Grande Highway (which later became West Miracle Mile), Oracle Road and Drachman Street through Tucson into a large commercial area. Williamson's proposal was called
Miracle Mile, inspired by the famous
Miracle Mile in
Los Angeles. Originally, Williamson thought of the name Parkway Boulevard but felt Miracle Mile better suited his new business area. Construction on Tucson's Miracle Mile started in 1937, with roadway improvements along Oracle Road (US 80 and
US 89). The improved roadway was intended to handle large volumes of traffic safely and promote business growth, while also attracting national attention. Construction also included the placement of two giant
traffic circles at Casa Grande Highway and Drachman Street. Both were built by the
Tanner Construction Company. The initial construction of Miracle Mile cost $200,000. In 1937, the eastern terminus of SR 84 was extended southeast along Miracle Mile, US 80 and US 89 to the intersection of Benson Highway and 6th Avenue. In 1940, SR 84 became the subject of cultural and political controversy. Two German tourists were observed by locals, giving the
Nazi salute to an SR 84 reassurance marker along Miracle Mile in Tucson. Up to this point, the Arizona State Route shields sported a
swastika inside an arrowhead below the highway number, which was meant to represent a
Native American peace symbol. Careful observation by highway officials concluded the swastika in use was the incorrect design for the Native American mark, but unintentionally matched the symbol used by
Nazi Germany. Upon the discovery, the
Arizona Highway Department ordered immediate replacement of all state highway shields to avoid association with
Adolf Hitler and the
Nazi Party. Several
motels in Tucson began construction the same year along Miracle Mile. After weathering through the tire and gas shortages of
World War II, business exploded along Miracle Mile due to a postwar population boom in Arizona causing a high demand for motel rooms. Even more businesses and motels were constructed throughout the late 1940s. By the 1950s, Miracle Mile was a thriving business district with several iconic neon signed motels and restaurants. Though it was a state highway, the initial construction cost was covered by the city of Tucson through passage of a city bond issue. SR 84A began construction on December 27, 1950. The
Santa Cruz River was diverted into a man made channel away from SR 84A during construction to prevent the river from flooding the new highway in the future. The first section of SR 84A between Miracle Mile (SR 84) and Congress Street opened to traffic on December 20, 1951 with the second section under construction. At first, this road didn't have any interchanges south of Miracle Mile. By 1958, large sections of SR 84 between Picacho and Tucson had been rebuilt into a
four lane divided highway. Between 1952 and 1955, the Highway 90 Association lobbied heavily within the state of Arizona to extend
U.S. Route 90 west to San Diego from its terminus at US 80 in
Van Horn, Texas. The proposed route laid forward by the Association would, enter near
San Simon and exit at the California border in
Yuma. US 90 would replace SR 84 between Tucson and Gila Bend, with the rest of the proposed route replacing
SR 86 and being concurrent with US 80. The effort began to pay off as several road and highway commissions in Arizona approved the US 90 extension. The
American Association of State Highway and Transportation Officials was set to make the ultimate decision regarding the proposed US 90 extension in December 1955. By 1956 however, the US 90 extension had not occurred, with SR 84, SR 86 and US 80 still comprising the direct route between
New Mexico and Yuma. Between 1961 and 1962, SR 84 was reconstructed into I-10 from Miracle Mile to
Picacho. Construction of I-10 through
Marana resulted in its downtown area being demolished. In 1966, SR 84 was truncated to an interchange with SR 87 and I-10 in Picacho. In 1973, SR 84 was truncated in the west to its current terminus at Exit 151 of I-8 west of Casa Grande. I-8 replaced it from Casa Grande to Gila Bend. On October 17, 1997, a portion of SR 84 was given to local jurisdictions, between SR 87 near Eloy and downtown Casa Grande at SR 287 and SR 387. SR 84 still serves as the only east–west thoroughfare in
Stanfield, Arizona, though it has been largely supplanted as a major road by I-8. Although the section between Casa Grande and I-10 near Picacho is no longer signed and is mostly maintained by local agencies, ADOT still considers said section as a part of SR 84. ==Junction list==