Grace Power, who went missing from St Albans on Friday, November 17, has been found safe and well.
The 16-year-old previously disappeared on Monday, October 30, before being found earlier this month.
She has links to Cheshunt and Harlow in Essex and police officers had been increasingly worried about her welfare.
Grace previously went missing in September from an address in New Southgate, London, and was found several days later in Waltham Cross.
It is not known where she went during her latest absence.
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