Highway 152
From Santa Cruz County history wiki
State Highway 152 (officially "California State Route 152") runs east from its beginning at Highway 1 in Watsonville, becomes Main Street in Watsonville, then exits the county over the Santa Cruz Mountains at Hecker Pass.
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.