Interstate 40

Interstate 40
source
Name	Interstate 40
Route type	Interstate Highway
Route number	40
Length mi	2556
Established	1956
Direction a	West
Terminus a	Barstow, California
Direction b	East
Terminus b	Wilmington, North Carolina
States	California; Arizona; New Mexico; Texas; Oklahoma; Arkansas; Tennessee; North Carolina

Interstate 40 is a major transcontinental Highway corridor traversing the southern United States from California to North Carolina, linking the Pacific Ocean with the Atlantic Ocean. The route connects desert communities such as Barstow and Kingman to metropolitan centers including Flagstaff, Albuquerque, Amarillo, Oklahoma City, Little Rock, Memphis, Nashville, and Raleigh. Conceived as part of the Federal-Aid Highway Act of 1956, the corridor succeeded preexisting alignments of U.S. Route 66, U.S. Route 70, and U.S. Route 64 in many segments and remains vital for long-distance freight movement, regional commuting, and intercity travel.

Route description

Beginning near Barstow, the western segment proceeds eastward through the Mojave Desert and links to Needles and Kingman before entering the Colorado Plateau at Flagstaff. The highway crosses the Little Colorado River basin and skirts the Grand Canyon National Park corridor while intersecting routes to Phoenix and Las Vegas. Continuing into New Mexico, the alignment traverses Gallup, Albuquerque, and Clines Corners, skirting the Sangre de Cristo Mountains approaches to Santa Fe via connector routes. In Texas, a brief concurrency navigates the Panhandle near Amarillo before the corridor advances into Oklahoma City, intersecting major radial routes to Tulsa and Wichita. The Arkansas section passes through Fort Smith and Little Rock, crossing the Arkansas River and linking with corridors to Memphis. Entering Tennessee, the route serves Jackson and Memphis suburbs, joins an urban expressway through Nashville and Knoxville, and crosses the Great Smoky Mountains foothills toward Asheville. The eastern terminus approaches Wilmington via the coastal plain, connecting with ports and ferry links to Cape Fear and regional seaports.

History

Planning for the corridor dates to early 20th‑century auto trails, notably the National Old Trails Road and the Bankhead Highway, later consolidated into numbered U.S. Highways such as U.S. Route 66 and U.S. Route 70. The Federal-Aid Highway Act of 1956 authorized a national network, and federal planners adopted the east–west corridor that became the present route. Construction milestones included the completion of challenging segments across the Mojave Desert and the elevated viaducts near Asheville to span rugged terrain. Urban segments prompted controversies in Nashville, Knoxville, and Little Rock over routing, eminent domain, and neighborhood displacement, while preservationists cited structures associated with Route 66, including motels, diners, and service stations in Holbrook, Winslow, and Gallup. Subsequent upgrades addressed capacity via widening projects in Oklahoma and Tennessee, interchange reconstructions near Oklahoma City, and the addition of safety improvements following high‑visibility incidents involving hazardous cargo near Albuquerque and Memphis.

Major intersections

The corridor intersects numerous principal arteries: at its western approach it meets the Interstate 15 corridor near Barstow and provides access to I-17 and U.S. Route 93 toward Phoenix and Las Vegas. In Flagstaff the corridor connects with U.S. Route 180 and links to State Route 89A toward the Grand Canyon. Near Albuquerque it intersects Interstate 25 and U.S. Route 550, facilitating north–south freight flows toward Denver and Santa Fe. The Amarillo segment crosses Interstate 27 and U.S. Route 287 toward Lubbock and the Texas Panhandle. Approaching Oklahoma City the corridor meets Interstate 35 and Interstate 44, while in Little Rock it intersects Interstate 30 and U.S. Route 167. The Memphis metropolitan area sees junctions with Interstate 55, Interstate 240, and corridors to Jackson, Mississippi. Traversing Nashville the route interfaces with Interstate 65 and Interstate 24, and eastward links include Interstate 81 and U.S. Route 23 toward the Appalachian region. Near its eastern terminus the corridor meets U.S. Route 117 and state routes that serve Wilmington and nearby port facilities.

Auxiliary routes

A network of auxiliary three‑digit interstates and spurs serve metropolitan areas along the corridor. Notable connectors include the urban loop serving Memphis, radial spurs feeding Oklahoma City and Nashville, and beltways around Little Rock and Albuquerque. These auxiliary routes link to arterials such as U.S. Route 61, U.S. Route 67, Interstate 540, and Interstate 240, providing redundancy for freight diversions during incidents. Several state departments of transportation, including agencies in California, Arizona DOT, New Mexico Department of Transportation, Oklahoma Department of Transportation, and Tennessee Department of Transportation, coordinate upgrades, signage, and interchange design with metropolitan planning organizations like those in Memphis and Nashville.

Notable features and landmarks

The corridor passes proximate to cultural and natural landmarks including Grand Canyon National Park approaches, the roadside attractions of Route 66 in Holbrook and Winslow, and the high‑desert landscapes around Flagstaff and Petrified Forest National Park. Urban stretches abut civic centers such as the historic districts of Albuquerque and Little Rock, river crossings over the Mississippi River at Memphis, and entertainment districts in Nashville and Asheville. Engineering accomplishments include long desert causeways, mountain viaducts near Asheville and Knoxville, and major river bridges spanning the Arkansas River and Mississippi River. The corridor also provides access to logistics hubs at the Port of Wilmington, intermodal yards near BNSF Railway and Union Pacific Railroad terminals, and military installations such as nearby Fort Bragg and reserve centers that rely on the route for strategic mobility.

Category:Interstate Highways in the United States