Historic Bawtry Hall is on the market after being put up for sale by its owners.
The Grade II listed house, built in 1785, was a key base for the RAF and was a Bomber Command Headquarters during the Second World War.
After being sold by the RAF in the mid 1980s, the building was bought by Action Partners Corporation, a Christian organisation, and has been used as teaching and conference centre for the past 24 years.
However manager Emma Deakin said the trustees had taken the decision to close the hall on December 31 and a buyer is now being sought, with the asking price rumoured to be in the region of £1.5 to £2 million.
She said: “We have already received expressions of interest from several parties but we are not in a position to go into greater detail at this time.”
A statement on the Hall’s website said that bookings were still being taken and it would be “business as usual” until the end of 2013.