Interstate 40 (I-40) is a part of the Interstate Highway System that travels 2,556.61 miles (4,114.46 km) from Barstow, California, to Wilmington, North Carolina. In North Carolina, I-40 travels 420.21 miles (676.26 km) across the entirety of the state from the Tennessee state line along the Pigeon River Gorge to U.S. Highway 117 (US 117) and North Carolina Highway 132 (NC 132) in Wilmington. I-40 is the longest Interstate Highway in North Carolina and is the only Interstate to completely span the state from west to east.
Traveling from west to east, I-40 connects the three major regions of North Carolina—Western North Carolina, the Piedmont, and Eastern North Carolina. In the Piedmont region, I-40 connects the Piedmont Triad and Research Triangle metropolitan regions. Included in these regions are the cities of Raleigh, Greensboro, Durham, and Winston-Salem which represent the second through fifth largest cities in the state, respectively. In addition, I-40 connects the cities of Asheville and Hickory in Western North Carolina, Wilmington in Eastern North Carolina, and many smaller communities along its route. The landscapes traversed by I-40 include the Blue Ridge Mountains, the foothills of Western North Carolina, suburban communities, and the urban core of several Piedmont cities, along with Eastern North Carolina farmland. There are five auxiliary Interstates in the state related to I-40: I-140, I-240, I-440, I-540, and I-840. I-40 formerly had one business loop which primarily ran through Winston-Salem and briefly was extended through Greensboro.