Shields for California's primary and auxiliary Interstate highways. There are eight primary Interstate highways and twenty-three auxiliary Interstate highways in California. Interstate 5 (I-5) - Runs from the United States-Mexico border in San Ysidro, San Diego to the Oregon state line. Interstate 8 (I-8) - Runs from Nimitz Boulevard and Sunset Cliffs Boulevard in San Diego to the Arizona state line. Interstate 9 (I-9) - Runs from I-5 at Wheeler Ridge to the Oregon state line north of Dorris, CA. Interstate 10 (I-10) - Runs from California State Route 1 in Santa Monica to the Arizona state line. Interstate 15 (I-15) - Runs from I-5 in San Diego to the Nevada state line at Primm, NV. Interstate 40 (I-40) - Runs from I-5 just west of Bakersfield to the Arizona state line. Interstate 70 (I-70) - Runs from I-5 nearby La Jolla Ranch (west of Fresno) to the Nevada state line nearby Sylvania, NV. Interstate 80 (I-80) - Runs from US 101 in San Francisco to the Nevada state l...