California was the home state of Hill Valley. From Hill Valley, one could access San Francisco and Fresno by rail, road, or skyway.
In 1985, California was one of the few states that offered personalized license plates. One was printed for use on the DeLorean time machine that read OUTATIME.
In 1992, Emmett Brown discussed hydro-electric power at the Colorado River, which flowed through California, as well as Colorado, Utah, Nevada, Arizona, and Mexico.
In 2015, California license plates consisted of barcodes. It is unknown whether this practice continued in other states.
Behind the scenes
California was also where the majority of filming for the Back to the Future trilogy took place. Scenes for Back to the Future were shot in Los Angeles, Hollywood, Burbank, Arleta, Pacoima, Newhall, City of Industry (La Puente), Whittier, Pasadena and South Pasadena and Universal City. Scenes in Back to the Future Part II added El Monte, Monrovia and Long Beach to the list. Back to the Future Part III took the crew to locations in Tuolemne County in Northern California outside of Jamestown and Sonora, and then back to Oak Park, Port Hueneme and Oxnard in Southern California.