U.S. 12 runs from Detroit, MI to Aberdeen, WA. It is still the only U.S. route left in Detroit (US 10, US 16, US 112, and US 25 also ran to downtown Detroit, forming a five-way intersection there).
U.S. 13 links Morrisville, PA to Fayetteville, NC. It incorporates the Chesapeake Bay Bridge-Tunnel in Virginia, and the majority of its routing is actually east of U.S. 1.
U.S. 14 runs from Chicago, IL to Yellowstone National Park, WY. It goes through Pierre, SD, a state capital not served by the Interstate system.
U.S. 15 goes from Painted Post, NY to Walterboro, SC. The northernmost portion of its route has been designated as a Future I-99 Corridor.
U.S. 16 is a rather short highway linking Rapid City, SD to Yellowstone National Park, WY. It originally extended to Detroit before the Interstate system was constructed. The original route also included a ferry connection between Muskegon, MI and Milwaukee, WI.
U.S. 17 runs from Winchester, VA to Punta Gorda, FL. Much of its routing is along the Atlantic shoreline between the Hampton Roads metropolis in Virginia and Jacksonville, FL.
U.S. 18 links Milwaukee, WI to Orin, WY.
U.S. 19 goes from Erie, PA to Memphis, FL, near Tampa. It splits into US 19E and US 19W at Bluff City, TN. The two branches rejoin in Yancey County, NC.
U.S. 20 is currently the longest road in the United States, running from Boston, MA to Newport, OR. Until 1940, the original western terminus was at Yellowstone National Park.
