The collision happened around 7:10 a.m. near Pacific Street and Glasgow Avenue.
The girl was walking in a marked crosswalk when the driver of an SUV going about 40-50 mph failed to stop for the pedestrian, striking her. The vehicle then fled the scene.
The girl was initially described as having life-threatening injuries. By the afternoon, officials confirmed she had died. Her name was not being released until her family was notified.
The vehicle was described as a tan GMC SUV. The driver was an adult Hispanic or African-American female, wearing eyeglasses with brown hair and described as heavyset.
Anyone with information is asked to call Officer Brewer at the San Bernardino CHP Office at (909) 383-4247.