Interstate 40 (I-40) is an east–west
Interstate Highway
The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Hi ...
that has a section in the US state of
Arizona
Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...
, connecting sections in
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
and
New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
. The Interstate is also referred to as the Purple Heart Trail to honor those wounded in combat who have received the
Purple Heart
The Purple Heart (PH) is a United States military decoration awarded in the name of the president to those wounded or killed while serving, on or after 5 April 1917, with the U.S. military. With its forerunner, the Badge of Military Merit, ...
. It enters Arizona from the west at a crossing of the
Colorado River
The Colorado River () is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and in northern Mexico. The river, the List of longest rivers of the United States (by main stem), 5th longest in the United St ...
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
Albuquerque ( ; ), also known as ABQ, Burque, the Duke City, and in the past 'the Q', is the List of municipalities in New Mexico, most populous city in the U.S. state of New Mexico, and the county seat of Bernalillo County, New Mexico, Bernal ...
. The highway has major junctions with
U.S. Route 93 (US 93; the main highway connecting
Phoenix and
Las Vegas
Las Vegas, colloquially referred to as Vegas, is the most populous city in the U.S. state of Nevada and the county seat of Clark County. The Las Vegas Valley metropolitan area is the largest within the greater Mojave Desert, and second-l ...
,
Nevada
Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...
) in Kingman and again approximately to the east and
I-17 I17 may also refer to:
* Interstate 17, an Interstate Highway located entirely within the state of Arizona, United States
* Japanese submarine ''I-17'', a B1 type submarine of the Imperial Japanese Navy
* Polikarpov I-17, a Soviet single-seat figh ...
(the freeway linking Phoenix to northern Arizona) in Flagstaff.
For the majority of its routing through Arizona, I-40 follows the historic alignment of
US 66. The lone exception is a stretch between Kingman and
Ash Fork where US 66 took a more northerly, less direct route that is now
State Route 66 (SR 66). Construction of I-40 was ongoing in the 1960s and 1970s and reached completion in 1984. With the completion of I-40 in 1984, the entire routing of US 66 had been bypassed by Interstate Highways which led to its decertification a year later in 1985.
Route description
California to Flagstaff

I-40 enters Arizona from California at a bridge that crosses the
Colorado River
The Colorado River () is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and in northern Mexico. The river, the List of longest rivers of the United States (by main stem), 5th longest in the United St ...
at
Topock
Topock ( Mojave: Tuupak) is a small unincorporated community and census-designated place (CDP) in Mohave County, Arizona, United States. As of the 2020 census, the population within the CDP was 2. Topock and the surrounding region have a ZIP C ...
in
Mohave County
Mohave County occupies the northwestern corner of the U.S. state of Arizona, one of 15 counties in the state. As of the 2020 census, its population was 213,267. The county seat is Kingman, and the largest city is Lake Havasu City. It is th ...
. It heads east from Topock and begins to curve toward the north at
Franconia
Franconia ( ; ; ) is a geographical region of Germany, characterised by its culture and East Franconian dialect (). Franconia is made up of the three (governmental districts) of Lower Franconia, Lower, Middle Franconia, Middle and Upper Franco ...
, completing the curve at
Yucca
''Yucca'' ( , YUCK-uh) is both the scientific name and common name for a genus native to North America from Panama to southern Canada. It contains 50 accepted species. In addition to yucca, they are also known as Adam's needle or Spanish-bayon ...
. The Interstate continues to head north until it reaches
Kingman. In this city, I-40 has a junction with
US 93 at exit 48. US 93 heads toward the northwest from this interchange to
Hoover Dam
The Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado, Black Canyon of the Colorado River (U.S.), Colorado River, on the border between the U.S. states of Nevada and Arizona. Constructed between 1931 and 1936, d ...
and
Las Vegas
Las Vegas, colloquially referred to as Vegas, is the most populous city in the U.S. state of Nevada and the county seat of Clark County. The Las Vegas Valley metropolitan area is the largest within the greater Mojave Desert, and second-l ...
. US 93 south begins to run concurrently with I-40 east as they both swing eastward through Kingman. The two later separate at exit 71 as US 93 heads toward the south toward
Phoenix while I-40 continues east toward Flagstaff. Along the way, I-40 passes through the town of Seligman, then, at
Ash Fork, it meets
SR 89, the former U.S. Route that heads south to
Prescott Prescott may refer to:
People
Given name
* Prescott E. Bloom, American lawyer and politician
* Prescott Bush, American banker and politician
* Samuel Prescott Bush, American industrialist
* Prescott F. Hall, American lawyer, author and eugenicist ...
. Next, it passes through
Williams, where it has an interchange with
SR 64 (exit 165), which heads north toward
Grand Canyon National Park
Grand Canyon National Park is a List of national parks of the United States, national park of the United States located in northwestern Arizona, the 15th site to have been named as a national park. The park's central feature is the Grand Canyo ...
. I-40 continues to the east to
Flagstaff, where it has a major junction with
I-17 I17 may also refer to:
* Interstate 17, an Interstate Highway located entirely within the state of Arizona, United States
* Japanese submarine ''I-17'', a B1 type submarine of the Imperial Japanese Navy
* Polikarpov I-17, a Soviet single-seat figh ...
at exit 195. I-17 heads south from this interchange to Phoenix.
Flagstaff to New Mexico
East of Flagstaff, I-40 heads toward the east-southeast direction as it goes through the town of
Winslow. It continues toward this direction until it reaches
Holbrook, where it curves toward the northeast. Along this stretch, it passes through
Petrified Forest National Park
Petrified Forest National Park is a national park of the United States in Navajo and Apache counties in northeastern Arizona. Named for its large deposits of petrified wood, the park covers about , encompassing semi-desert shrub steppe as wel ...
and continues to the northeast, passing through
Chambers, and enters the
Navajo Nation
The Navajo Nation (), also known as Navajoland, is an Indian reservation of Navajo people in the United States. It occupies portions of northeastern Arizona, northwestern New Mexico, and southeastern Utah. The seat of government is located in ...
. The highway still continues to the northeast to the
New Mexico
New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...
border southwest of
Gallup, New Mexico
Gallup is a city in McKinley County, New Mexico, United States, with a population of 21,899 as of the 2020 United States census, 2020 census. A substantial percentage of its population is Native Americans in the United States, Native American, wi ...
, as it continues on toward
Albuquerque
Albuquerque ( ; ), also known as ABQ, Burque, the Duke City, and in the past 'the Q', is the List of municipalities in New Mexico, most populous city in the U.S. state of New Mexico, and the county seat of Bernalillo County, New Mexico, Bernal ...
.
History
With the exception of a stretch between Kingman and Flagstaff, I-40 directly replaced the famed US 66 across northern Arizona. Where possible, US 66 was upgraded to
Interstate standards
Standards for Interstate Highways in the United States are defined by the American Association of State Highway and Transportation Officials (AASHTO) in the publication ''A Policy on Design Standards: Interstate System''. For a certain highway t ...
to become I-40 directly. Exceptions to this were through the central business districts of the cities and towns that US 66 passed through, and I-40 had to be built as a bypass outside the cities. On October 26, 1984, after the last section of I-40 was completed in Williams, US 66 was removed from the
state highway system of Arizona. The portions through cities that did not overlap I-40 would become
business loops of I-40.
Before the U.S. Routes
The routing of a road near the current corridor of I-40 in Arizona was first surveyed and built between 1857 and 1859. Lt.
Edward Beale and his soldiers built the road along the 35th parallel that would come to be known as the
Beale Wagon Road from
Fort Smith, Arkansas
Fort Smith is the List of municipalities in Arkansas, third-most populous city in Arkansas, United States, and one of the two county seats of Sebastian County, Arkansas, Sebastian County. As of the 2020 United States census, 2020 census, the pop ...
, to the
Colorado River
The Colorado River () is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and in northern Mexico. The river, the List of longest rivers of the United States (by main stem), 5th longest in the United St ...
to serve as a military wagon road. The road was a popular route for immigrants during the 1860s and 1870s until the
transcontinental railroad
A transcontinental railroad or transcontinental railway is contiguous rail transport, railroad trackage that crosses a continent, continental land mass and has terminals at different oceans or continental borders. Such networks may be via the Ra ...
was built across northern Arizona in the 1880s. In the early 1900s, the road became part of the
National Old Trails Road
National Old Trails Road, also known as the Ocean-to-Ocean Highway, was established in 1912, and became part of the National Auto Trail system in the United States. It was long and stretched from Baltimore, Maryland (some old maps indicate N ...
, a transcontinental route from
Baltimore
Baltimore is the most populous city in the U.S. state of Maryland. With a population of 585,708 at the 2020 census and estimated at 568,271 in 2024, it is the 30th-most populous U.S. city. The Baltimore metropolitan area is the 20th-large ...
, Maryland, to
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
, and the
National Park to Park Highway
The National Park-to-Park Highway was an auto trail in the United States in the 1910s and 1920s, plotted by A. L. Westgard. It followed a large loop through the U.S. West, West, connecting twelve National Park (US), national parks:
*Rocky Mountai ...
, an auto trail linking the national parks of the west.
U.S. Route 66
In the 1920s, as a nationwide system of highways called the
United States Numbered Highways
The United States Numbered Highway System (often called U.S. Routes or U.S. Highways) is an integrated network of roads and highways numbered within a nationwide grid in the contiguous United States. As the designation and numbering of these h ...
was being developed, the route through was given the designation of US 60. This designation was controversial since designations that are multiples of 10 are assigned to transcontinental east–west routes and this route was a diagonal route from
Chicago, Illinois
Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...
, to
Los Angeles, California
Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...
. As a compromise to states east of Chicago that felt US 60 should go through their state,
a different route was given the number 60, while the route from Chicago to Los Angeles was given the number 66.
By 1927, the routing of US 66 through Arizona had been laid out, but none of it had been paved yet. By 1935, nearly the entire route had been paved, with the lone exceptions being a short stretch northeast of
Valentine and a stretch between
Peach Springs
Peach Springs () is a census-designated place (CDP) in Mohave County, Arizona, United States. The population was 1,098 at the 2020 census. Peach Springs serves as the administrative headquarters of the Hualapai people and is located on the Hual ...
and
Seligman. By 1938, the entire route in Arizona had been paved. In 1953, US 66 was realigned between the California border and
Kingman to an alignment to the southeast to avoid the mountain curves and grades of the original alignment. By 1961, several sections of the highway had been expanded to a four-lane divided highway in anticipation of the coming Interstate Highway. Four-lane sections included a section near
Ash Fork, another section east of Winslow, and a section east of Holbrook near the Petrified Forest National Monument.
Planning
In Flagstaff, several different alternatives were considered as a potential routing of the new Interstate through the area. The alternatives consisted of a routing north of downtown, south of downtown, through downtown along the
Santa Fe Railroad
The Atchison, Topeka and Santa Fe Railway , often referred to as the Santa Fe or AT&SF, was one of the largest Class 1 railroads in the United States between 1859 and 1996.
The Santa Fe was a pioneer in intermodal freight transport; at variou ...
right-of-way near the alignment of US 66, and a more elaborate alternative of a routing above downtown on a long overpass. In January 1959, the Flagstaff Chamber of Commerce recommended to the
Bureau of Public Roads
The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program a ...
that the route south of downtown be used which was approved by the Flagstaff City Council and the Board of Supervisors for
Coconino County
Coconino County is a County (United States), county in the North Central Arizona, North-Central part of the U.S. state of Arizona. Its population was 145,101 at the 2020 United States census, 2020 census. The county seat is Flagstaff, Arizon ...
. This recommendation was accepted and would become the planned routing of I-40 in Flagstaff.
Business owners along US 66 were opposed to this routing as it would draw motorists away from main through route of the time, US 66. As a result, they created the No By-Pass Committee and sent a proposal to the Chamber of Commerce's Roads and Highways Committee to conduct a study of the feasibility of a route for I-40 through downtown along the Santa Fe railroad right-of-way. The Committee sent an inquiry to the railroad concerning the proposal. The railroad rejected the proposed rerouting of their main rail lines, citing that it would result in worse grades than what currently exists, and, in order to reduce those grades, considerable lengthening of the rail line would be required.
With a routing through town now out of the question, the business owners along US 66 drafted a city ordinance, known as Initiative 200, that was filed with the city of Flagstaff in November 1959 to appear on the general election ballot in March 1960. The ordinance would, in effect, ban all new commercial businesses on I-40, all routes leading from I-40 to US 66, and the area between I-40 and US 66.
In a record voter turnout, voters overwhelmingly voted against the ordinance by a vote of 2,280 to 556.
In 1965, the routing of I-40 west of Kingman was being reconsidered from the planned route through
Needles, California
Needles is a city in San Bernardino County, in the Mojave Desert region of Southern California. Situated on the western banks of the Colorado River, Needles is located near the California border with Arizona and Nevada. The city is accessible v ...
, to a route to the north passing through
Searchlight
A searchlight (or spotlight) is an apparatus that combines an extremely luminosity, bright source (traditionally a carbon arc lamp) with a mirrored parabolic reflector to project a powerful beam of light of approximately parallel rays in a part ...
in southern Nevada and connecting with I-15 further north of its present connection with I-15. The rationale for the proposal was that it would be an overall shorter route and would cost much less to construct. The proposal was met with stiff opposition, including all four
US senator
The United States Senate is a chamber of the bicameral United States Congress; it is the upper house, with the U.S. House of Representatives being the lower house. Together, the Senate and House have the authority under Article One of the ...
s from California and Arizona sending the
Secretary of Commerce
The United States secretary of commerce (SecCom) is the head of the United States Department of Commerce. The secretary serves as the principal advisor to the president of the United States on all matters relating to commerce. The secretary rep ...
letters requesting that the routing through Needles be retained. This proposal was eventually abandoned in 1966, and the routing through Needles was kept.
Construction

The construction of the route of I-40 across Arizona took nearly 25 years to complete with the last segment being completed in 1984, much longer than the ambitious goal of finishing by 1972. By the end of 1960, had been completed with an additional being worked on. In 1964, construction was still on schedule with complete and an additional under construction. Funding was becoming an issue at this time as the state lacked the available funds to stay on pace with a 1972 completion goal. By 1967, Arizona had completed almost half of the highway with complete and another under construction. In 1968, the bypass around Flagstaff was complete with three interchanges, two at each end of where US 66 split off from I-40 to enter the city and one at the I-17 interchange. An additional interchange at Butler Avenue was completed a year later. One of the big improvements of I-40 over US 66 was the construction of the segment between Kingman and Ash Fork. The section is a more direct route between the two cities and travels as far as south of the US 66 alignment, bypassing
Hackberry and
Peach Springs
Peach Springs () is a census-designated place (CDP) in Mohave County, Arizona, United States. The population was 1,098 at the 2020 census. Peach Springs serves as the administrative headquarters of the Hualapai people and is located on the Hual ...
and creating
ghost-towns. Construction of the $69.1 million (equivalent to $ in ) segment was also to be a much safer route as the US 66 alignment had one of the highest fatality rates of any section of highway in Arizona. This section of the Interstate was complete in 1978. Construction of the $7.7 million (equivalent to $ in ) bypass around Winslow began in 1977. I-40 was completed in Arizona in 1984, with the completion of a section in Williams. This was also the last section of US 66 to be bypassed by the Interstate, which led to it being decertified by the
(AASHTO) the following year.
Exit list
See also
*
*
References
External links
*
{{Good article
40
Arizona
Transportation in Mohave County, Arizona
Transportation in Yavapai County, Arizona
Transportation in Coconino County, Arizona
Transportation in Navajo County, Arizona
Transportation in Apache County, Arizona