Police say Mary Barrios was struck by a car driven by a 38-year-old Chelsea man at about 7:40 p.m. Monday on Alewife Brook Parkway, near a shopping mall and the Alewife subway and bus station.
She may have been trying to cross the busy street when she was struck.
Police say Barrios had a Cambridge address but was originally from Chambersburg, Pa.
She was taken to Mount Auburn Hospital where she died of her injuries.
The driver's name has not been released because no charges have been filed.