Does anyone know what is the longest road in the United States? Hint it connects the Atlantic to the Pacific and is not an Interstate Highway. Give up? It’s U.S. Route 20, a 3,365 mile road that goes through 11 states. Starting in Boston, Mass. on Commonwealth Avenue near Fenway Park and ending in Newport, Oregon, U.S. Route 20 became the longest road in the country in 1963 after U.S. Route 6 was shortened in California.
Richard Weingroff, of the FHWA answers the question of the longest road in detail and describes its numbering and the northwest extension that was added from Yellowstone National Park to the state of Oregon.