Update 12pm: Alyssa O'Hanlon has been located safe and well.
Gardaí have thanked the public for their assistance.
Gardaí are asking for the public's help in finding a teenage girl from Dublin.
17-year-old Alyssa O'Hanlon has been missing from the Crumlin area since the early hours of yesterday morning.
She was last seen on Stanaway Avenue.
Alyssa is 5ft in height, with a slim build, long brown hair and blue eyes.
When last seen, she was wearing a black bubble jacket with a fur hood, black leggings and pink Nike Air Max trainers.
Gardaí are concerned for Alyssa and asking anyone who has seen her or who can assist in locating her is to contact Crumlin Garda Station on 01 - 6666200, the Garda Confidential Line on 1800 666 111 or any garda station.