In the U.S. state of California, Interstate 10, the major east-west Interstate Highway in the Southern United States, runs east from Santa Monica, California, on the Pacific Ocean, through Los Angeles and San Bernardino to the border with Arizona. In the Los Angeles area, it is known as the Santa Monica Freeway and San Bernardino Freeway, linked by a short concurrency on Interstate 5 (the Golden State Freeway) at the East Los Angeles Interchange. At the East LA Interchange, a short piece of the San Bernardino Freeway west of I-5 is part of the legislative definition of Route 10, but does not carry Interstate 10. This section of freeway, once a short Interstate 110 until 1968, is signed for I-10 eastbound and for U.S. Route 101 (its terminus, at the Santa Ana Freeway) westbound.

This route is part of the California Freeway and Expressway System CA Codes (shc:250-257) and is eligible for the State Scenic Highway System CA Codes (shc:260-284) .