Ackergill Tower in Caithness, once used by Oliver Cromwell to garrison his troops, was most recently run as a hotel - with actors Jack Nicholson and Michael Douglas among those who stayed at the castle.
Now, wealthy Episcopalian minister Dr Betsee Parker from Virginia has been given permission to turn the castle, which was recently valued at £3.9m, back into a single private home.
The widowed American philanthropist - the 17th Baroness of Lochiel - is reportedly going to use the former stronghold as a holiday home.
It comes after the 5* hotel and wedding venue - which charged up to £900 a night - shut in December, with the loss of 40 jobs.
The stunning castle sits on the rugged shoreline at Sinclair’s Bay on the northernmost tip of Scotland near Wick and is surrounded by a 3,000 acre private estate.
It was promoted to tourists using the North Coast 500 route - ‘Scotland’s Route 66’ - as ‘one of the finest hotels in the Highlands’.
A spokesperson for Clarenco, the current owner, said: “A transfer of ownership is imminent and Ackergill Tower will no longer be operating as a hotel.”
The tower is believed to have date from 1475.
In 1651, Oliver Cromwell is said to have used it to garrison his troops during his siege of the Keith’s Dunnottar Castle near Stonehaven when he was hunting for the Honours of Scotland.
John Campbell, 2nd Earl of Breadalbane and Holland then took possession of Ackergill Tower in repayment of debts owed to him by the Sinclair Clan in Scotland.
In 1986, the castle was sold and then underwent a two-year restoration before opening as an exclusive hotel and business venue.
The tower was sold again in 2009 by current owners AmaZing Venues - part of Clarenco - and got a five-star rating in 2012 after a £2m refurb.
The five-floor tower has 32 bedrooms and sits in 30 acres of ground with a lease for shooting and fishing in the surrounding 3,000 acres.
Ackergill also has the largest tree house in Europe which can sleep two people, as well as six cottages, a boathouse and a bothy.
Clarenco put the property on the market in 2015 for £4.5 million with Knight Frank, but last year the asking price was slashed to £3.9 million.
Dr Parker lodged an application with Highland Council on December 11, asking for permission to change it from a hotel to a home.
Planning documents said the house would be used for the “enjoyment” of the applicant.
Forty staff were made redundant shortly after the plans were submitted with the change of use approved on January 22.
In a decision notice issued, Dafydd Jones, planning manager at Highland Council, said: “Residential use is considered appropriate for the building because it re-establishes its original purpose and ensures its continued occupation.”
The minister, who has an estimated wealth of around £10 million, has carried out philanthropic work in Senegal, Kenya, and Sierra Leone.
Councillor Raymond Bremner, who represents East Caithness and Wick on Highland Council, has raised concerns about the sale.
He said: “The tower is an iconic place in the north and its closure will leave a bitter taste with many.
“The tower had a lot of staff who were knowledgeable and dedicated.
Councillor Bremner added: “I wish the new owner well.”