It expanded through the remainder of the 1950s by taking in the archives stored at the Dorset County Museum, and becoming the Diocesan Record Office in 1959.
In 1991 a new purpose-built office was opened on Bridport Road in Dorchester, with approximately 6 miles of shelving capacity in environmentally controlled repositories, including a special storage area for modern media.
The county's Local Studies Library was moved into the record office building in 2005, at which point it became the Dorset History Centre.
The oldest document in the collection is a charter from the Saxon king Edgar granting land in Cheselbourne which dates from 965 AD.
[12] The Dorset History Centre was one of the first archive services to go into partnership with a commercial organisation in order to digitise a significant percentage of its records and make these available online.