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.
Iowa Highway 3
Iowa Highway 3 is a state highway that runs from east to west across the state of Iowa. Highway 3 is the longest state highway in Iowa, at long. Iowa 3 begins at the South Dakota state line where it continues as South Dakota Highway 50 and ends at an interchange with U.S. Route 61 / U.S. Route 151. It is designated the American Veterans Memorial Highway for its entirety. It is located approximately halfway between Interstate 80 and Interstate 90.