When in 1859 the holdings of the Königliches Kartographisches Institut (Royal Cartographic Institute) were transferred to the Königliche Bibliothek (Royal Library), the map department was created as a separate unit. Since then the department has built up the largest map collection in Germany. In particular, large private collections were the important basis for a systematic collection development, and in 1919 the integration of the map archive of the Großer Preußischer Generalstab (Prussian Great General Staff) with its numerous hand-drawn maps of early land surveys further enhanced the value of the collection. 
Every year, around 10,000 new maps are added to the department’s holdings. This is especially due to the continuous support of the Deutsche Forschungsgemeinschaft (German Research Foundation) which funded the Special Subject Collection 28.1 Topographic Maps until 2015 and since 2016 it has funded the Specialised Information Service Cartography and Geodata. In October 2020, for the first time after World War II, the map department could be reunited at one site. From spring 2021 on it is open to its users in newly designed spaces.