The Cypress Freeway itself does not go through the Santa Cruz
mountains, but it is a part of the road that does. Highway 17
originally went from Santa Cruz through the mountains to along the
east shore of the San Francisco Bay and for its last two or so
miles became the Cypress. In 1985 the section from I-280 in San
Jose north to the MacArthur Maze interchange that leads to the Bay
Bridge, which includes the Cypress, was renamed I-880. The Santa
Cruz to I-280 portion through the mountains is still Highway
17.