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.
List of state highways in Utah
The longest contiguous highway signed as a Utah State Route is State Route 24 at . However, State Route 30 is longer at when the unsigned concurrencies with I-84, I-15, and US-89 are included. The longest highway of any type in Utah is U.S. Route 89 at . The shortest state route is State Route 231, a connector route in Fairview, though this route is unsigned. The shortest signed route is State Route 103 at long, connecting Hill Air Force Base to I-15 and SR-126.