U.S. Route 91 - History

History

At its peak, from 1947 to 1965, U.S. 91 extended from the Pacific Ocean at Long Beach, California to Coutts, Alberta. North of Riverside, California, U.S. 91 mostly paralleled modern I-15. There are some parts where U.S. 91/I-15 had divergent paths. The more southerly is from Littlefield, Arizona to Saint George, Utah where the two routes took different paths through the Arizona Strip. The more northerly and longer is the surviving portion of U.S. 91 from Brigham City to Downey, where Interstate 15 follows an old route of U.S. Route 191.

Utah first submitted a petition to AASHTO to have the U.S. 91 designation truncated in 1971. This petition was approved on June 21, 1971. However, the state did not take action until 1974. Utah officials co-ordinated a second petition with the transportation departments of California, Nevada and Arizona. In this unified petition officials in Utah proposed the number changeover take place in 1974. Nevada requested postponing the deletion of U.S. 91 as Nevada expected to complete the last piece of I-15 in 1975. Nevada officials suggested U.S. Route 40 be similarly truncated, as this highway largely duplicated Interstate 80 in the same states. Despite Nevada's request, the petition was submitted and approved in 1974.

Retracing the path of historic U.S. Route 91 is possible but difficult. In most cities the route of U.S. 91 is still in use as a local street or highway. In many rural areas, I-15 was literally built on top of the former U.S. 91.

The highway passed through the following states:

• California (until 1974)
• Nevada (until 1974)
• Arizona (10 miles (16 km) in the Arizona Strip, until 1974)
• Utah
• Idaho
• Montana (until 1980)