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.
South Carolina Highway 9
South Carolina Highway 9 (SC 9) is a major state highway in the U.S. state of South Carolina. The route runs from North Myrtle Beach to the North Carolina border upstate. The road is currently the longest state highway in South Carolina. It is signed as a north–south highway (with North Myrtle Beach as its southern terminus and the North Carolina border as its northern) though overall it runs in an east–west direction.