The body was struck by a taxi near Orangewood Avenue at about 8:30 p.m. after walking in front of it in the southbound lanes.
The 23-year-old woman from San Dimas was declared dead at the scene. Her name has not been released.
The taxi driver that hit her stopped, and the driver spoke to investigators.
The freeway was shut down while authorities investigated the accident, causing traffic to backup for miles.