US Highway 466 was the fourth branch route of Route 66, and the only one not included in the Joint Board of Interstate Highways’ 1925 plan of branch routes for US 66. The highway was not specified in the plan due to a controversy regarding whether the parent route was to be numbered as US 60 or US 66. A few years after the 66 designation had been approved and assigned to the mainline road, the American Association of State Highway Officials (AASHO, now AASHTO) approved US 466 in 1935. Unlike most of the other branches, however, US 466 was actually a true inter-state route.
In the original plan, US 466 began at a junction with US 66 in Kingman, Arizona. From there, it traveled westward through Las Vegas, Nevada, and continued on to meet up with 66 again at Barstow, California. US 466’s route then went on across the Central Valley of California. It passed through Tehachapi, Bakersfield, and Atascadero (crossing the El Camino Real, US Highway 101), until it reached its western terminus at Morro Bay on thePacific coast, totaling over 500 miles.
US 466 quickly became a preferred route for truckers and travelers from Arizona and Nevada bound for northern California. By using 466, motorists could avoid the longer route through Los Angeles and the difficult passes over the Sierra Nevada. Also, travelers heading in the opposite direction now had an easy route over to US 66, or US Highway 91, at that time one of the major north-south routes (US 91 would later be replaced, as well, by Interstate 15).
The status of US 466 as a major regional route sealed its fate when plans were laid for the new Interstate highways. By the early 1960s, it had disappeared completely between Kingman and Las Vegas, replaced by US Highway 93; from there to Barstow, it was replaced by Interstate 15. The last vestiges of US 466 were removed on July 1, 1964 when, as part of a highway renumbering project, California replaced the remaining routing of 466 with state routes 58 and 46. The entire length of the highway in California has been submitted many times for inclusion in the Interstate system, but has thus far not been approved. Nonetheless, the highway is still an important route through the central California area, and there are plans to upgrade it to freeway status.
Cooper, Casey, "Finding US 466", Historic California U. S. Highways. 2001. <http://gbcnet.com/ushighways/US466.html> (February 2004)
Droz, Robert V., "Sequential List of US Highways", US Highways From US 1 to US 830. July 2003. <http://www.us-highways.com/us1830.htm> (February 2004)
Weingroff, Richard F., "U.S. 666: Beast of a Highway?", Federal Highway Administration Highway History. June 2003. <http://www.fhwa.dot.gov/infrastructure/us666.htm> (February 2004)