The Department for Education has confirmed in a letter to Darlington MP Jenny Chapman that the Mowden Hall site in the town will close.
The decision is part of a review of buildings used by the department. It is expected that staff will be relocated to new site in Darlington or Newcastle.
More top news
Emma Jesson brings you Sunday night's forecast
Cold and clear with widespread frost on Sunday night. Sunny Monday then showers
A number of Britons are feared stranded on Mount Everest after the Nepal earthquake triggered a deadly avalanche on Saturday.