Police are appealing for potential witnesses to come forward following the sexual assault in the early hours of Sunday morning in the Shiregreen area.
The teenager was walking from the Green Lane area of Ecclesfield towards Sicey Avenue, Shiregreen, walking along Woolley Wood Bottom between 12.15am and 1.15am.
At some point during this journey, a black, second-generation Ford Focus is believed to have pulled up in front of the woman and just after this, an unknown person is alleged to have seriously sexually assaulted the woman.
Detective Constable Tim Bell, from South Yorkshire Police, said: “This incident is believed to have taken place in a populated residential area and we know that there are a number of houses that face onto these roads.
“I’d urge any residents living in that area to think back to the weekend and consider whether they saw or heard anything suspicious.
“Did you see a Ford Focus driving in the area that evening?
“The 19-year-old victim is receiving support from officers and we appreciate that this appeal may concern the local community, but we are working hard to identify the vehicle or the man as soon as possible.”
Anyone with information is asked to call police on 101 or email [email protected], quoting incident number 90 of July 17, 2016.