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.
Pacific Highway (United States)
Good roads advocate and road-building pioneer Sam Hill was perhaps the main motivating force behind building the original Pacific Highway as a "national auto trail"; from Blaine, Washington, on the Canada–US border, where he would build his Peace Arch, through Oregon to the Siskiyou Mountains of northwestern California. The road was built in the early 20th century—long before the U.S. Highway System was established. In 1923, its of pavement made it the longest continuous stretch of paved road in the world at the time. The Pacific Highway later extended north to Vancouver, British Columbia, and south through San Francisco to San Diego in Southern California.