US Route 789 was a proposed US Route which was known as the "Canada-to-Mexico Highway." US Route 789 was formally proposed to the American Association of State Highway Officials by the states of Arizona, New Mexico, Colorado, Wyoming and Montana during November 1950. The application was ultimately rejected but led to the formation of Multi-State Highway 789 between the Mexican border at Nogales, Arizona and Canadian border in Sweetgrass, Montana. Much of Multi-State Highway 789 would be removed by the mid-1960s but the routing does remain fully intact within Wyoming. Pictured as the blog cover is the multiplex of Wyoming State Route 789 and US Route 30 Business in Rawlins as seen in 2007 (picture taken by Jake Bear).
The history of the US Route 789 proposal and Multi-State Route 789
Conceptual US Route 789 was borne out of a desire by the Canada to Mexico Highway Association to obtain a new US Route designation through the states of Montana, Wyoming, Colorado, New Mexico and Arizona. The organization based out of Billings, Montana, had been organized during 1933 with the goal of obtaining a US Route designation for their promoted Canada-Mexico corridor.
A June 11, 1950, letter from the Wyoming State Highway Engineer to the American Association of State Highway Officials (AASHO) Executive Secretary requested insight on how to request a US Route designation on the behalf of the Canada to Mexico Highway Association. The letter notes that the Canada-to-Mexico Highways had been proposed numerous times with the last instance being during 1946. The letter noted an agreement had been made between Montana, Wyoming, Colorado, New Mexico and Arizona towards pursuing a US Route designation for the Canada-Mexico Highway. The Wyoming State Highway Engineer suggested a proposed number of "US Route 777" for the Canada-to-Mexico Highway.
The Wyoming State Highway Engineer sent another letter to the AASHO Executive Secretary on July 21, 1950, requesting a follow up to the letter sent on June 11, 1950.