The West Whiteland Township Police Department said 17-year-old Brittany Stanley has been missing since February 20th.
She is believed to be in the Philadelphia area.
Stanley is described as 5'2" tall and 180 pounds. She has brown eyes and brown hair with a tattoo of cherries, in black ink, on her left arm.
Police said she may be going by the name of "Lily."
Anyone with information on her whereabouts is asked to call West Whiteland Township Police at 610-363-0200 or 610-692-5100.