Derbyshire Record Office and Derbyshire Local Studies Library will close for seven weeks from December 21 for staff to move them from County Hall to a refurbished building in New Street, Matlock.
The services, based at County Hall in Matlock, will merge and move into a new building.
The building will house documents from across Derbyshire dating back nearly 800 years, taking up five miles of storage shelving.
Coun Andrew Lewer, Derbyshire County Council leader, said: “Our Record Office and Local Studies Library are two valued and popular services.
“Bringing them together in this new state-of-the art development is a very exciting time.”