Interstate 40

Interstate 40 (I-40) is a major east–west transcontinental Interstate Highway in the southeastern and southwestern portions of the United States. From west to east, it passes through California, Arizona, New Mexico, Texas, Oklahoma, Arkansas, Tennessee, and North Carolina. At a length of 2,556.61 miles (4,114.46 km), it is the third-longest Interstate Highway in the country, after I-90 and I-80.

Its western terminus is at I-15 in Barstow, California, while its eastern terminus is at a concurrency with U.S. Route 117 (US 117) and North Carolina Highway 132 (NC 132) in Wilmington, North Carolina. Major cities served by the Interstate include Flagstaff, Arizona; Albuquerque, New Mexico; Amarillo, Texas; Oklahoma City, Oklahoma; Fort Smith and Little Rock in Arkansas; Memphis, Nashville, and Knoxville in Tennessee; and Asheville, Winston-Salem, Greensboro, Durham, Raleigh, and Wilmington in North Carolina.

I-40 begins in the Mojave Desert in California, and then proceeds through the Colorado Plateau in Arizona and the southern tip of the Rocky Mountains in New Mexico. It then traverses the Great Plains through the Texas Panhandle and Oklahoma, and passes south of the Ozarks in Arkansas. The freeway crosses the Appalachian Mountains in Tennessee and North Carolina, before terminating in the Atlantic Coastal Plain near the Atlantic Ocean.

Much of the western part of I-40, from Barstow to Oklahoma City, parallels or overlays the historic U.S. Route 66. East of Oklahoma City, the route generally parallels US 64 and US 70. I-40 was established by the Federal-Aid Highway Act of 1956, and the numbering was subsequently approved on August 14, 1957, along with most of the rest of the system. The eastern terminus was initially planned to be located at I-85 in Greensboro, but the Federal Highway Administration later approved extending the route to its current eastern terminus in Wilmington. As a result, this was the last segment of I-40 to be completed upon its dedication in 1990.