The California Highway Patrol says the woman was walking after midnight in the eastbound lane of Rose Avenue, east of Amber Avenue, when an oncoming driver hit her.
The 58-year-old died at the scene.
Investigators say that she was wearing dark clothing, and the driver did not see her.
The CHP said alcohol and drugs were not factors in the crash. Officers are investigating to determine why the woman was walking in the roadway.
Editor's Note: Law enforcement originally said the victim was male. Authorities have updated their case report to indicate that the victim was female. The story has been updated with this new information.