Interstate 5 (I-5) is a major north–south route of the Interstate Highway System in the United States, stretching from the Mexican border at the San Ysidro crossing to the Canadian border near Blaine, Washington. The segment of I-5 in California runs 796.53 miles (1,281.89 km) across the length of the state from San Ysidro to the Oregon state line south of the Medford metropolitan area. It is the longest Interstate in California and accounts for more than half of I-5's total length. It is the more important and most-used of the two major north–south routes on the West Coast of the US, the other being US Route 101 (US 101), which is primarily coastal. I-5 links the major California cities of San Diego, Santa Ana, Los Angeles, Stockton, Sacramento, and Redding. The San Francisco Bay Area is about 80 miles (130 km) west of the highway. I-5 is known colloquially as "the 5" to Southern California residents and "5" to Northern California residents due to varieties in California English. I-5 also has several named portions: the John J. Montgomery Freeway, San Diego Freeway, Santa Ana Freeway, Golden State Freeway, and West Side Freeway.
