Jane Walker, 72, has not been seen since she left her home in Selby in the early hours of this morning (November 12).
She is described as 5ft 6ins tall, average build, with dark curly hair thinning on top. She was wearing a green jumper, black trousers and grey flat white shoes, possibly plimsoles.
North Yorkshire Police said they are urgently trying to find her.
A statement from the force said: "Officers are very concerned for her welfare, and are urging anyone who sees her, or knows where she is, to get in touch straight away.
"Please call North Yorkshire Police on 101, quoting reference NYP-12112021-0263."
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