California State Route 238 is a north-south highway in the southeastern part of the San Francisco Bay Area. A divided multilane surface highway, it connects Interstate 580 in Castro Valley, California and Interstate 680 in Fremont, California. It goes through Hayward and Union City parallel to the Hayward Hills . It formerly contained a segment of east-west freeway now designated as Interstate 238 and, until Interstate 680 was completed in the area and supplanted it completely as a through route, extended to San José, California at its intersection with U.S. Highway 101.
Before California massively renumbered its state highways in 1964, this highway was known as California State Route 9. It was long scheduled for replacement by a freeway.
