More than a million historical objects reflecting Cumbria's history have been moved to a new base in Carlisle.
The archives office at Carlisle Castle has moved to an £8.2m purpose built centre at Petteril Bank.
Cumbria County Council said if all the documents stored in the building were piled on top of each other, the stack would be more than four miles high.
The archive includes the Royal Charter of the City of Carlisle from 1316 which bears the seal of Edward II.
The archive provides an insight into the places and people of Cumbria from the 12th century to the present day.
It also preserves vital practical information on things such as boundaries and rights of way.
The centre, which has taken nine years to complete, is expected to open to the public in April 2011.
Previously the county council had hoped to open the new building in January 2011, but construction delays meant that it has now been decided to open slightly later than planned.
The centre was funded by a £4.8m grant from the Heritage Lottery Fund.
It has allowed the dilapidated, Georgian, Grade II* listed Lady Gillford's House to be fully renovated and transformed by the addition of a new glass-fronted building which houses the main archive vault and public study area.
The archives are housed in a temperature and humidity controlled hi-tech vault protected by a gas fire protection system.