U.S. Route 40 or U.S. Highway 40 (US 40), also known as the Main Street of America, is a major east–west United States Highway traveling across the United States from the Mountain States to the Mid-Atlantic States. As with most routes whose numbers end in a zero, US 40 once traversed the entire United States. It is one of the first U.S. Highways created in 1926 and its original termini were in San Francisco, California, and Atlantic City, New Jersey. US 40 currently ends at a junction with I-80 in Silver Summit, Utah, just outside Salt Lake City. West of this point US 40 was functionally replaced with I-80, and as these segments of I-80 were constructed the western portion of US 40 was truncated several times.