Karen Black, from Worksop in Nottinghamshire, was last seen in Cleethorpes, Lincolnshire, on 10 November 2006.
A case review in 2015 saw four men arrested on suspicion of murder in July 2016, but they were later released without charge.
Her niece Roxanne Davis said "no one in the family can be at peace".
Mother-of-one Ms Black, 34, was seen on a train from Worksop to Cleethorpes and then stayed at a guesthouse in the town.
Nottinghamshire Police and Humberside Police changed the case from missing persons to a murder investigation in 2008 but it was a review in 2015 which lead to the arrests.
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The four men arrested, aged 40, 45, 54 and 58, were all from the Cleethorpes area.
Ms Davis said: "It is mind-blowing. You can't imagine that someone in your family could just one day be there and then the next minute you don't know what has happened to them.
"No one in the family can be at peace with it because we don't know what to think, whether she is alive or something bad has happened to her - it is just awful."
Det Insp Andy Bateman of Nottinghamshire Police said they hoped new lines of enquiry and the appeal would find the culprit.
He said: "This is a heart-breaking appeal from a girl who loved her aunt very much and I'm now appealing to the people of Cleethorpes within this tight-knit community.
"I do believe that someone somewhere has that piece of information that could provide the assistance we need and subsequently the closure for the family."
The family of a woman missing for 10 years has appealed to the "tight-knit" community where she vanished.