<P> U.S. Route 20 ( US 20 ) is an east -- west United States highway that stretches from the Pacific Northwest all the way to New England . The `` 0 '' in its route number indicates that US 20 is a coast - to - coast route . Spanning 3,365 miles ( 5,415 km ) , it is the longest road in the United States , and the route roughly parallels that of Interstate 90 ( I - 90 ) . There is a discontinuity in the official designation of US 20 through Yellowstone National Park , with unnumbered roads used to traverse the park . </P>
<P> U.S. Route 20 ( US 20 ) is an east -- west United States highway that stretches from the Pacific Northwest all the way to New England . The `` 0 '' in its route number indicates that US 20 is a coast - to - coast route . Spanning 3,365 miles ( 5,415 km ) , it is the longest road in the United States , and the route roughly parallels that of Interstate 90 ( I - 90 ) . There is a discontinuity in the official designation of US 20 through Yellowstone National Park , with unnumbered roads used to traverse the park . </P>
what is the longest highway in the united states
what is the longest highway in the united states
U.S. Route 20 ( US 20 )
U.S. Route 20 ( US 20 )