Interstate 40 (I-40) is part of the Interstate Highway System that spans 2,556.61 miles (4,114.46 km) from Barstow, California, to Wilmington, North Carolina. In Tennessee, I-40 traverses the entirety of the state from west to east, from the Mississippi River at the Arkansas border to the northern base of the Great Smoky Mountains at the North Carolina border. At a length of 455.28 miles (732.70 km), the Tennessee segment of I-40 is the longest of the eight states on the route, and the longest Interstate Highway in Tennessee.