U.S. Highway 91, also known as the "Old Highway 91," is a north-south route that runs through the western United States. It stretches from the border of Mexico in California to Montana, covering approximately 1,200 miles. The highway passes through several states, including Nevada and Utah, and serves as a vital connection for local communities and travelers. Originally designated in 1926, U.S. Highway 91 was part of the early national highway system. Over the years, parts of the highway have been replaced or incorporated into the Interstate Highway System, but it remains an important historical route, reflecting the development of road travel in America.