U.S. Route 66 was officially decommissioned in 1985.
The highway was one of the original routes in the U.S. Numbered Highway System, established on November 11, 1926. It linked Chicago with Santa Monica across eight states and became a major corridor for westward migration, especially during the Dust Bowl of the 1930s. John Steinbeck later helped popularize its “Mother Road” nickname.
Route 66 declined as the Interstate Highway System expanded. New interstates bypassed many towns and shifted long-distance traffic away from the older road. The American Association of State Highway and Transportation Officials formally removed U.S. 66 from the national highway system on June 26, 1985.
A common mix-up is 1984: Arizona had already removed its section after Interstate 40 replaced it, but nationwide decommissioning occurred in 1985. Historic Route 66 still survives as a marked heritage and tourism route, although it is no longer a continuous U.S. Highway.