U.S. Route 20
U.S. Highway 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 , it is the longest road in the United States, and particularly from Newport, Oregon to Boston, Massachusetts, the route is roughly parallel to that of the newer Interstate 90 (I-90), which is in turn the longest Interstate Highway in the U.S. There is a discontinuity in the official designation of US 20 through Yellowstone National Park, with unnumbered roads used to traverse the park.
North Carolina Highway 20
The original NC 20 was at one time the longest numbered route in North Carolina, running from the Tennessee border to the port city of Wilmington, a distance of . After the introduction of U.S. highways in North Carolina in 1934, the route was carved up between routes US 19, US 70, US 74, US 76, and US 17.