Rare Cropsey landscape in export bar
A temporary export bar has been placed on Jasper Francis Cropsey's painting Richmond Hill in the Summer of 1862.
A rare example of a UK-owned British landscape by an American painter, the government needs to raise almost £5 million to keep it in the country.
Lord Inglewood, of the Reviewing Committee on the Export of Works of Art and Objects of Cultural Interest (RCEWA), called it "a rare survivor".
"I hope funds can be raised to save this wonderful painting," he added.
The ruling by Culture Minister Ed Vaizey follows a recommendation to defer export by the RCEWA.
The committe made the decision on the grounds that the painting was of outstanding significance for the study of the relationship between British and American painting in the 19th Century.
Born in New York's Staten Island, Cropsey - a leading light of the 'Hudson River School' of landscape painting - showed regularly at the Royal Academy in the 1850s.
One early assessment of his Richmond Hill painting said it depicted "a view unsurpassed for its purely English beauty".
Cropsey was forced to sell the piece after he ran up huge debts entertaining in London. The work has remained in Britain ever since.
An earlier export licence application for the painting in February 2000 was withdrawn after the RCEWA recommended that export be deferred for three months to allow time for a potential purchaser to be identified.
Any decision about the painting's current export will now be deferred until 7 April 2013, with a possible extension to 7 August if a serious intention to purchase the painting is found.
Earlier this week a temporary export bar was placed on two works by George Stubbs that gave the 18th Century British public their first chance to see what a kangaroo and a dingo looked like.