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 U.S. Highways in Michigan
In Michigan, the US Highway System covers about of mainline highways and another of special routes. There are 13 mainline highways and 30 special routes in total, including one business route that is unsigned. Two of the mainline highways in the Upper Peninsula exit the state and re-enter, resulting in two discontinuous segments of highway for each in Michigan. The longest US Highway in the state is US Highway 23 (US 23) at just over spanning from the Ohio state line north to the Straits of Mackinac in the Lower Peninsula, while the shortest is the segment of US 8 south of Norway in Dickinson County. Special routes range in length from about for Business US 2 (Bus. US 2) in Ironwood to for Bus. US 131 in Kalamazoo.