The British Library Map Collections form the national collection of cartographic materials. The focal point of the Map Collections is the Map Library which 
provides access to maps, atlases and globes of all parts of the world dating back to the 15th century. It also acts as a Library-wide advisory service for cartographic 
materials dating back to the early medieval period.  
The Map Library holds the most comprehensive, publicly accessible collection of Ordnance Survey maps in the world. They also hold Ordnance Survey of Northern 
Ireland (OSNI) and Ordnance Survey of Ireland Maps (OSI).  
The archives comprise materials in a variety of formats including maps, atlases, globes, adverts, postcards, printing plates, coins and medals. Twentieth-century 
series mapping is supported by a comprehensive historical collection, universal in its coverage. Legal deposit, international exchange, donation and purchase 
provide regular and substantial additions to these collections.