Highway 129
From Santa Cruz County history wiki
State Highway 129 (officially "California State Route 129") runs east from its beginning at Highway 1 in Watsonville, following the Pajaro River to exit the county and continue to connect with US Route 101 in San Benito County.
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.