U.S. Highway 420 (Decommissioned)
U.S. 420 is one of several U.S. routes that have been decertified in Wyoming. Along with U.S. 116, 185, 216, and 285, U.S. 420 was decommissioned early, in 1936. U.S. 320 was decommissioned in 1938, and U.S. 187 was decommissioned years later, in 1982.
During its ten-year life (between 1926 and 1936), U.S. 420 was a short connector route from the mainline U.S. 20 at Cody to U.S. 310 at Deaver. This highway was about 41 miles long. At the same time, a road between Cody and Thermopolis via Meeteetse was being developed; this road was designated Wyoming 420.
In 1936, U.S. 420 and U.S. 116 were replaced by U.S. 14. The section of U.S. 310 between Deaver and Lovell were concurrently U.S. 14 and U.S. 310. Farther east, U.S. 16 between Moorcroft and South Dakota became U.S. 14, and U.S. 216 was recommissioned as U.S. 16. Wyoming 420 south of Cody kept its designation.
A few years later, in 1939, U.S. 14 was rerouted to its current mainline, between Cody and Burgess Junction via Greybull and Shell Canyon. For that one year, what was formerly U.S. 14 and U.S. 420 between Cody and Deaver was recommissioned as Wyoming 420. The short cut-off between Powell and Lovell came into existence in 1939 as Wyoming 310. So, in 1939, while war was heating up in Europe, the Wyoming Highway Department was determining whether the whole road between Thermopolis and Deaver via Cody and Powell should be called Wyoming 420.
Alas, it was not to be. In 1940, the highway was reconstructed between U.S. 310 at Lovell and U.S. 14 at Burgess Junction via Medicine Wheel. The highway department then renamed the whole road, from Cody to Burgess Junction via Powell, as Wyoming 14. Wyoming 14 included not only Wyoming 420 from Cody to Powell, but also Wyoming 310 through Lovell. The northernmost portion of Wyoming 420, between Powell and Deaver, was recommissioned as Wyoming 114, a designation that remains to this day. This entire route would later become Alternate U.S. 14 in 1965.
Meanwhile, Wyoming 420 south of Cody persevered for another five years. In 1945 -- the end of World War II and the beginning of the Cold War -- Wyoming 420 was recommissioned as Wyoming 120 between Thermopolis and Cody. Several years later, Wyoming 120 was extended north into Montana to connect to Montana 72.
For more on the routing of U.S. 420, see the U.S. 14 page.