The young bicyclist was struck at the intersection of Wiker and Frances avenues around 6:40 p.m., the police detailed in the release.
The girl had been riding her bike without a helmet going north on Frances Avenue, investigators explained. When she crossed Wiker Avenue she collided with a 27-year-old mom's silver Nissan Rogue with her young daughter as a passenger.
The police noted, "There were no reported injuries to either party in the vehicle," adding that, "This intersection is controlled by stop signs for traffic traveling north and south on Francis Ave. The posted speed limit is 25 mph on Wiker Ave."
The girl on the bicycle was initially taken to Penn Medicine Lancaster General Hospital but was transferred to Penn State Hershey Medical Center.
Anyone who witnessed the crash or has information about it, is asked to call the West Lampeter Township Police at 717-464-2421.
Click here to follow Daily Voice Pennside-Mount Penn and receive free news updates.