The two were crossing the highway at River Street around 12:45 a.m. when they were struck by a northbound vehicle, Santa Cruz police said.
The 24-year-old woman died at a hospital. The child was in stable condition. Their identities have not been released; police said the woman was from Santa Cruz County.
The driver remained at the scene and cooperated with police, and an early investigation found “no evidence of driver impairment or negligence,” the police said.
There is a traffic light and crosswalks at the intersection. The police report did not indicate if the pedestrians were crossing with a green light.
Highway 1 is eight lanes at that point, and the speed limit is 40 mph.