Elise Donoghue was reported missing from the Acomb area of York at around 1pm Saturday.
Police said they had since tracked her to the West Yorkshire area. Anybody who sees her is asked to dial 999.
A North Yorkshire police spokesperson said: "She is also known to travel by train between Leeds and York.
"She was last seen wearing black leggings and black, knee high suede boots and is thought to be wearing large looped earrings.
"Elise is described as white, 5ft 2in tall, blonde hair with a medium build."
Anyone with information about Elise's whereabouts should call police on 101 with the reference number 12180083173.