Interstate 640 (I-640) is an east–west auxiliary Interstate Highway in Knoxville, Tennessee. It serves as a bypass for I-40 around Downtown Knoxville and is also an alternative route for traffic passing between I-40 and I-75. All trucks carrying hazardous cargo through Knoxville are required to use I-640. It has a total length of 10.80 miles (17.38 km) and runs approximately three miles (4.8 km) north of downtown through the northern neighborhoods of Knoxville.