High Quality Content by WIKIPEDIA articles! Interstate 210 (I-210) and State Route 210 (SR 210) together form a contiguous highway, called the Foothill Freeway, in the Greater Los Angeles area of the U.S. state of California. The western portion of the route is an auxiliary Interstate Highway, while the eastern portion is a state highway. The entire route was upgraded to Interstate Highway standards by 2007, and the California Department of Transportation (Caltrans) has requested permission to re-sign the eastern portion as an Interstate Highway.