Barbara Messerschmidt, 69, of Barrington, has been charged in connection with the crash, police announced on Wednesday.
According to investigators, Messerschmidt admitted to driving southbound in the 700 block of North Haddon Avenue around 8:30 p.m. Saturday and was unable to stop before hitting the girl.
Messerschmidt allegedly told police she panicked and fled the scene without stopping to help.
Haddonfield police say they were able to track down Messerschmidt's vehicle from evidence left at the scene.
The 11-year-old girl who was struck suffered serious injuries to her head and leg and was last reported to be in stable condition.