The Directorate of Colonial Surveys was founded by the Colonial Office in 1946 and its brief, at the outset of its thirty-eight years existence, was to fulfill two key purposes. Firstly, to provide national geodetic frameworks throughout the Colonial Empire that would not only contribute to understanding of the size and shape of the earth, but would constitute the basis of accurate mapping. Secondly, to produce such mapping using modern methods based on aerial photography.

In 1957, with the imminent decolonisation of many British territories, it was renamed the Directorate of Overseas Surveys (DOS). The remit of the organisation was expanded to include countries within and without the Commonwealth, and meant the Directorate's surveyors - based in Tolworth in suburban west London - ultimately surveyed fifty-five countries around the world. These included countries throughout Australasia and the Far East, the Indian Subcontinent, Middle East, Africa, Caribbean, South America, British Antarctic Territory and islands in the Pacific, Atlantic, Indian and Mediterranean.

Government reviews during the 1970s led to it being merging into the Ordnance Survey (OS) in 1984 whence it was known as the Overseas Surveys Directorate (OSD). In 1991, following completion of the last significant aid-funded mapping projects, its name was changed one final time to Ordnance Survey International and its main activity became consultancy, primarily in Eastern Europe. It was closed in 2001.