In 1946, the Colonial Office established the Directorate of Colonial Surveys (DCS), to be a central survey and mapping organisation for British colonies and protectorates.
In 1957, DCS was renamed the Directorate of Overseas Surveys (DOS) to reflect the independence of many former Colonies. Some non-Commonwealth countries such as Ethiopia, Liberia, Sudan, and Yemen Arab Republic were mapped by DOS between 1975 and 1991.
During the 1970s, government reviewed the DOS’ purpose. Then, in 1984, the organisation was merged with Ordnance Survey and given a new title: Overseas Surveys Directorate, OS (OSD).
Ordnance Survey already had its own international division. When the two organisations were merged in 1984, all international aerial photographs, maps, and survey data were amalgamated into one working collection. It was named Technical Information and Support Services and kept that title for seven years, before being renamed International Library in 1991.
By 1991 the last significant, aid-funded mapping projects had been completed by OSD and all survey parties had been disbanded. OSD’s title was changed to OS International and its priorities turned to consultancy, mainly in Eastern Europe, while traditional map production gradually declined.
In 2002, Ordnance Survey deemed its International Library no longer needed for operational purposes. Responsibility for these public records then passed to The National Archives (TNA). Working with OS staff and advised by specialists, the material was appraised, and determined what would be kept, and where. Public access to the International Library in Ordnance Survey head office ceased in March 2003.
During 2003 and 2004, Ordnance Survey and TNA sought suitable custodians of all parts of the collection and relocated them. The public could access the historical archives again from the end of 2004.