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.
Special routes of U.S. Route 95
The route now known as US 95 Spur was previously known as US 630 and US 30N. US 630 was an east–west United States highway. It was decommissioned in or around 1931. With a length of around , it was the shortest US route ever signed. It was concurrent with US 30N for its entire length. An earlier route numbered US-630 was proposed from Echo, Utah (northeast of Coalville) to Ogden, Utah, but was never signed in the field. U.S. Route 30N was a split route off of US-30 and was coterminous with US 630 at its west end in Oregon. East of Weiser, it was concurrent with what is now US-95 to Fruitland, Idaho, where it reconnected with US-30.