File:Interstate 5 and California Aqueduct South of Kettleman City, California (21394579140).jpg

Interstate 5 (I-5) is a major north–south route of the Interstate Highway System in the U.S. state of California. It begins at the Mexico–United States border at the San Ysidro crossing, goes north across the length of California and crosses into Oregon south of the Medford-Ashland metropolitan area. It is the more important and most used of the two major north-south routes on the Pacific Coast, the other being U.S. Route 101, which is primarily coastal and always west of the Interstate.

Route 101 begins at a point in downtown Los Angeles intersecting the Interstate. Then the routes diverge until in the northernmost areas of California. They can average more than 150 miles (240 km) apart.

This highway links the major California cities of San Diego, Santa Ana, Los Angeles, Stockton, Sacramento, and Redding. Among the major cities not directly linked by Interstate 5 but which are connected by local highways to it are San Francisco, Oakland and San Jose, all of which are about 80 miles (130 km) west of the highway.

From SR 99 to south of Tracy, I-5 is known as the Westside Freeway. It parallels SR 33, skirting along the far more remote western edge of the great Central Valley, and thus here is removed from the major population centers such as Bakersfield, Fresno and Modesto, with other state highways providing connections. I-5 still runs within the vicinity of Avenal, Coalinga, Los Banos, and the handful of other smaller cities on the western edge of the Central Valley. For most of this section, the Path 15 electrical transmission corridor follows the highway, forming an infrastructure corridor along with the California Aqueduct.

en.wikipedia.org/wiki/Interstate_5_in_California