Highway 9

State Highway 9 (officially "California State Route 9") runs north from its beginning at Highway 1 in Santa Cruz, parallelling the San Lorenzo River to near its headwaters, then swinging east over the Santa Cruz Mountains, crossing Highway 35 to descend into Saratoga and Los Gatos in Santa Clara County before ending at Highway 17.

Only one state highway originates elsewhere on both ends and passes through Santa Cruz County: Highway 1. Five highways originate in Santa Cruz County and pass out of it: Highway 9, Highway 17, Highway 35, Highway 129, Highway 152. One begins and ends within the county: Highway 236.