The museum has in its custody archives of a private and personal nature from private companies and from clubs and societies. The largest archive is that which belonged to The Røros Copper Works.
The archive from the Røros Copper works is divided into two sections: The oldest and largest section is that which was taken over by the National Archives in Trondheim in the 1930s. Material from around 1900 – 1930 and onwards, as well as older duplicates are kept in the Røros Museum.
Of the other private archives, which have been donated to the museum or deposited here, we should mention The Society for the Solidarity of Women, The Røros Cattle Breeders Association, The Røros Womens’ Hospital Association, The Røros Forest Owners’ Club and The Røros Telephone Company. In addition, the archive contains single items of documents and records.