Interstate 40 (I-40) is a major 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 ...
in the United States, stretching from
Barstow, California
Barstow is a city in San Bernardino County, California, in the Mojave Desert of Southern California. Located in the Inland Empire region of California, the population was 25,415 at the 2020 United States census, 2020 census. Barstow is an impor ...
, to
Wilmington, North Carolina
Wilmington is a port city in New Hanover County, North Carolina, United States. With a population of 115,451 as of the 2020 United States census, 2020 census, it is the List of municipalities in North Carolina, eighth-most populous city in the st ...
. The segment of I-40 in California is sometimes called the Needles Freeway. It passes through the eastern fringe of the
Inland Empire
The Inland Empire (commonly abbreviated as the IE) is a metropolitan area and region inland of and adjacent to coastal Southern California, centering around the cities of San Bernardino and Riverside, and bordering Los Angeles County and Or ...
metropolitan area, going east from its western terminus at
I-15 in Barstow across the
Mojave Desert
The Mojave Desert (; ; ) is a desert in the rain shadow of the southern Sierra Nevada mountains and Transverse Ranges in the Southwestern United States. Named for the Indigenous peoples of the Americas, indigenous Mohave people, it is located pr ...
in
San Bernardino County
San Bernardino County ( ), officially the County of San Bernardino and sometimes abbreviated as S.B. County, is a county located in the southern portion of the U.S. state of California, and is located within the Inland Empire area. As of th ...
past the
Clipper Mountains to
Needles, before it crosses over 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 ...
into
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 ...
east of Needles. All of I-40 in California are in San Bernardino County.
Route description

The entirety of I-40 in California is designated as Route 40 in the state highway system. The California Streets and Highways Code defines it as follows in section 340: "Route 40 is from
Route 15 at
Barstow to the
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 ...
state line near
Topock, Arizona via
Needles."
I-40 goes through the
Mojave Desert
The Mojave Desert (; ; ) is a desert in the rain shadow of the southern Sierra Nevada mountains and Transverse Ranges in the Southwestern United States. Named for the Indigenous peoples of the Americas, indigenous Mohave people, it is located pr ...
on the entirety of its run through California. The highway starts its eastward journey at a junction with
I-15 in
Barstow. The freeway passes through
Marine Corps Logistics Base Barstow
Marine Corps Logistics Base Barstow is a United States Marine Corps supply and maintenance installation located in the Mojave Desert east of Barstow, California, Barstow, in San Bernardino County, California, San Bernardino County, Southern Califo ...
before leaving the city limits. I-40 provides access to the town of
Daggett but passes south of the town. After passing south of the
Barstow-Daggett Airport, I-40 goes through
Newberry Springs and
Ludlow
Ludlow ( ) is a market town and civil parish in Shropshire (district), Shropshire, England. It is located south of Shrewsbury and north of Hereford, on the A49 road (Great Britain), A49 road which bypasses the town. The town is near the conf ...
before traveling along the south end of
Mojave National Preserve. Several miles east of the preserve, I-40 intersects
U.S. Route 95 (US 95), and the two highways run concurrently into the city of
Needles. In Needles, US 95 continues south while I-40 continues east through
Mojave National Preserve and across 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 ...
into
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 ...
.
The maximum speed limit for the entire California segment of I-40 is .
I-40 is part of the
California Freeway and Expressway System and is part of the
National Highway System,
a network of highways that are considered essential to the country's economy, defense, and mobility by the
Federal Highway Administration
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 ...
.
I-40 is eligible for the
State Scenic Highway System,
but it is not officially designated as a scenic highway by the
California Department of Transportation
The California Department of Transportation (Caltrans) is an Executive (government), executive department of the U.S. state of California. The department is part of the Government of California#State agencies, cabinet-level California State Tran ...
.
I-40 from I-15 to the Arizona state line is known as the Needles Freeway, as named by Senate Concurrent Resolution 1 in 1968.
History
In 1957, the California Department of Highways proposed that the route be numbered as I-30 because of the already existing
US 40 in the state. However, this was rejected, and, eventually, US 40 was decommissioned in favor of
I-80.
Today, the Needles Freeway replaced the former
US 66 across the Mojave Desert. As a result, a number of communities along the former route, like
Amboy, have become
ghost-towns.
In the early 1960s,
Project Carryall, a component of
Project Plowshare, would have detonated 22 nuclear explosions to excavate a massive roadcut through the
Bristol Mountains to accommodate a better alignment of I-40 and a new rail line. This proposal was abandoned by the California State Department of Highways in 1968. The section between Ludlow and Needles was constructed using conventional explosives and excavation and designed with culverts for migrating
Bighorn sheep
The bighorn sheep (''Ovis canadensis'') is a species of Ovis, sheep native to North America. It is named for its large Horn (anatomy), horns. A pair of horns may weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates th ...
and water tanks. It opened to traffic on April 13, 1973.
A sign at that start of I-40 in Barstow showing the distance to
Wilmington, North Carolina
Wilmington is a port city in New Hanover County, North Carolina, United States. With a population of 115,451 as of the 2020 United States census, 2020 census, it is the List of municipalities in North Carolina, eighth-most populous city in the st ...
, had been stolen multiple times.
Exit list
Related routes
California does not have any auxiliary Interstate Highways associated with I-40.
One
business loop of I-40 exists in the state, running through
Needles. It is also designated as Historic Route 66 since it follows the former routing of
US 66.
See also
*
References
External links
Interstate 40 @ Interstate-Guide.com
@ Interstate-Guide.com
at California @ AARoads.com
at California Highways
{{3di, 40
40
Southern California freeways
Roads in San Bernardino County, California
California