Sinead Heaton is white, with bleach blonde hair, and is described as looking in her late 40s or early 50s.
She is local to the Blackburn area and is known to often frequent the town centre.
Police said they are "growing increasingly concerned for her welfare" since she has not been seen or heard from for a number of days.
If you have seen Sinead or know of her whereabouts, you can contact Lancashire Police on 101 and quote log number: LC-20200509-1329