San Bernardino County history: Interstate 15 – Welcome to San Bernardino County

"San Bernardino County Update", yellow arrowhead and "SBCounty.gov

Signs display "Freeway Entrance" and "Interstate 15 North" on a clear day with mountains in the distance. — *Interstate 15 on ramp sign in the Mojave Desert.*

Interstate 15 is a major highway in the western United States. It begins near the U.S. – Mexico border in San Diego County and extends north through California, Nevada, Arizona, Utah, Idaho and Montana.

During the 1960s and 1970s, controversy arose over where I-15 should be routed. At the time, regional routes included state highways 31 and 71, U.S. Route 395, and a proposed Highway 81, which would have run north and south through Fontana.

Since that option was eliminated, planners considered two alternatives, including upgrading highways 31 and 71 routes as I-15 or constructing a new interstate along the proposed Highway 81 corridor. The Highway 81 plan would have followed Locust Avenue in eastern Fontana, but opposition from residents led city officials to support the 31-71 route proposal. State officials ultimately agreed and those routes became the new alignment for I-15.

After the rerouting, San Bernardino and Riverside officials raised concerns that the freeway bypassed their downtown areas. As a compromise, in 1972, Caltrans officials designated a new alignment through the Inland Empire, which included renaming U.S. 395 as Interstate 15E.

I-15E was the only interstate in California, and one of only two in the nation to have a letter in its name. The designation reportedly caused confusion in Caltrans’ computer systems. The route was also assigned the internal designation of 194. In 1982, it was renumbered as Interstate 215 north of State Route (SR) 60, and State Route 215 south of SR 60. After upgrades to interstate standards, the entire route became I-215 in 1994.

Due to rapid population growth, the I-15 corridor remains the focus of several transportation projects. In 2020, Virgin Trains USA signed a 50-year lease to use the I-15 right of way between the Victor Valley and the Nevada border for its XpressWest high-speed rail service.

The information in this historical feature was originally part of a video series produced by the Assessor-Recorder-County Clerk’s office.

Additional County Update News – April 30, 2026