The General Archive of Simancas is an official archive located in the Castle of Simancas, in the town of Simancas, province of Valladolid, Castile and León, Spain. It was founded in 1540, making this the first official archive of the Crown of Castile.
The chronological evolution of the institution has been influenced by the history of the Crown of Castile. The moments of strength or weakness of the Spanish monarchy have been reflected in the regularity of documents' arrivals or conversely in the shortages of resources. A major milestone occurred in 1588, when Philip II of Spain issued the charter of the Archives of Simancas, a key document for understanding the management of both this archive and others in the peninsula. Also, the damage suffered during the Spanish War of Independence had a major impact on the institution.
Currently, the AGS is a cultural institution funded by the Ministry of Culture of Spain dedicated to conservation, cataloging and research. These activities have brought about the reputation of the archive as one of the cornerstones of the Iberian Peninsula in its preservation and custody of documents.