Alnwick Castle is the latest in a line of popular North East venues to stay closed in response to the coronavirus pandemic.
The tourist attraction, known as one of the filming locations for some of the Harry Potter films, was set to open at the end of March for its summer season.
But the castle doors will remain shut following Government advice on 'social distancing'.
The announcement comes as measures to combat the spread of the sars-cov-2 virus, which causes the disease covid-19, are ramped up, with UK schools closing their doors indefinitely to the majority of children on Friday.
A castle spokesperson said: "Following Government advice on Monday, March 15, we have taken the decision to delay the opening of Alnwick Castle to visitors for the foreseeable future.
"This is in the interest of looking after the health and wellbeing of our visitors, employees and the wider community. The castle was due to open on March 27.
"All tickets booked for a visit between March 27 and June 30 will receive a full refund and our team will be in touch in due course."
She added: “We will be monitoring the situation closely. Updated information will be available on the Alnwick Castle website as and when things change.”
Hulne Park, also owned by Northumberland Estates, which runs the castle, will remain open to the public for free. And the wider estates business will “continue to operate normally as far as possible”.
The move is likely to cause uncertainly for the seasonal workers in the Northumberland town who had planned to take up jobs at the castle over the season.
The spokesperson said that the situation would “hopefully” cause only a “temporary” delay in employment - and said that a yet-to-be confirmed form of financial compensation would be considered.
In December, more than 100 posts were advertised for everything from cafe workers and till operators to historical reenactors and tour guides to join the castle team until it closed for the winter.
The National Trust, which operates a number of historic buildings, stately homes and other attractions throughout the North East, on Wednesday made a similar move, closing all its UK properties to the public.
However, National Trust gardens and parklands are now open free of charge where possible, and visitors have been encouraged to enjoy them while practicing social distancing.
Meanwhile, Alnwick Garden remains open to the public, with a "completely modified our cleaning and sanitisation process", with bosses encouraging the public to enjoy the attraction's "vast open spaces with an abundance of fresh air".
